Controlled vapor deposition of multilayered coatings adhered by an oxide layer

ABSTRACT

An improved vapor-phase deposition method and apparatus for the application of multilayered films/coatings on substrates is described. The method is used to deposit multilayered coatings where the thickness of an oxide-based layer in direct contact with a substrate is controlled as a function of the chemical composition of the substrate, whereby a subsequently deposited layer bonds better to the oxide-based layer. The improved method is used to deposit multilayered coatings where an oxide-based layer is deposited directly over a substrate and a SAM organic-based layer is directly deposited over the oxide-based layer. Typically a series of alternating layers of oxide-based layer and organic-based layer are applied.

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 10/862,047, filed Jun. 4, 2004 and entitled“Controlled Deposition of Silicon-Containing Coatings Adhered By AnOxide Layer”, which is currently pending. Application Ser. No.10/862,047 is related to, but does not claim priority under ProvisionalApplication Ser. No. 60/482,861, filed Jun. 27, 2003 and entitled:“Method And Apparatus for Mono-Layer Coatings”; Provisional ApplicationSer. No. 60/506,846, filed Sep. 30, 2003, and entitled: “Method Of ThinFilm Deposition”; Provisional Application Ser. No. 60/482,861, filedOct. 9, 2003, and entitled: “Method of Controlling Monolayer FilmProperties”; and, to U.S. patent application Ser. No. 10/759,857, filedJan. 16, 2004, which claims priority under the provisional applicationslisted above.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to a method, and to the resultingstructure which is created by depositing a multilayered coating in amanner such that the thickness, mechanical properties, and surfaceproperties of the multilayered coating provide functionality on ananometer scale. The method is described with reference to at least oneoxide-based layer which is chemically bonded to an underlying structure,and to at least one overlying layer which is adhered by chemical bondingto the oxide layer.

2. Brief Description of the Background Art

Integrated circuit (IC) device fabrication, micro-electromechanicalsystems (MEMS) fabrication, microfluidics, and microstructurefabrication in general make use of layers or coatings of materials whichare deposited on a substrate for various purposes. In some instances,the layers are deposited on a substrate and then are subsequentlyremoved, such as when the layer is used as a patterned masking materialand then is subsequently removed after the pattern is transferred to anunderlying layer. In other instances, the layers are deposited toperform a function in a device or system and remain as part of thefabricated device. There are numerous methods for depositing a thin filmor a coating, such as, for example: Sputter deposition, where an ionplasma is used to sputter atoms from a target material (commonly ametal), and the sputtered atoms deposit on the substrate; chemical vapordeposition, where activated (e.g. by means of plasma, radiation, ortemperature, or a combination thereof) species react either in a vaporphase (with subsequent deposition of the reacted product on thesubstrate) or react on the substrate surface to produce a reactedproduct on the substrate; evaporative deposition, where evaporatedmaterial condenses on a substrate to form a layer; and, spin-on,spray-on, wiped, or dipped-on deposition, typically from a solventsolution of the coating material, where the solvent is subsequentlyrinsed or evaporated off to leave the coating material on the substrate.

In many applications where the wear on the coating is likely to occurdue to mechanical contact or where fluid flow is to occur over thesubstrate surface on which the layer of coating is present, it ishelpful to have the coating chemically bonded directly to the substratesurface via chemical reaction of active species which are present in thecoating reactants/materials with active species on the substratesurface. In addition, particular precursor materials may be selectedwhich are known to provide particular functional moieties.

With respect to layers and coatings which are chemically bonded to thesubstrate surface, there are a number of areas of particular currentinterest. By way of example, and not by way of limitation, such coatingsmay be used for biotechnology applications, where the surface wettingproperties and functionality of the coating are useful for analyticalpurposes, for controlling fluid flow and sorting of fluid components,and for altering the composition of components which come into contactwith the surface, for example. Such coatings may also be used in thefield of integrated circuitry, or when there is a combination ofintegrated circuitry with mechanical systems, which are referred to asmicro-electromechanical systems, or MEMS. Due to the nanometer sizescale of some of applications for coatings exhibiting specializedfunctionality, a need has grown for improved methods of controlling theformation of the coating, including the formation of individual layerswithin a multilayered coating. Historically, these types of coatingswere deposited by contacting a substrate surface with a liquid phase.While this technique enables efficient coating deposition, it frequentlyresults in limited film property control. In the case of coating asurface of a nanometer scale device, use of liquid phase processinglimits device yield due to contamination and capillary forces. Morerecently, deposition of coatings from a vapor-phase has been used in anattempt to improve coating properties. However, the common vapor-phasedeposition methods may not permit sufficient control of the molecularlevel reactions taking place during the deposition of surface bondinglayers or during the deposition of functional coatings, when thedeposited coating needs to function on a nanometer (nm) scale.

For purposes of illustrating methods of coating formation whereliquid-based precursors are used to deposit a coating on a substrate, orwhere vaporous precursors are deposited to form a coating on asubstrate, applicants would like to mention the following publicationsand patents which relate to methods of coating formation, by way ofexample. Most of the background information provided is with respect tovarious chlorosilane-based precursors; however it is not intended thatthe present invention be limited to this class of precursor materials.In addition, applicants would like to make it clear that some of thisBackground Art is not prior art to the present invention. It ismentioned here because it is of interest to the general subject matter.

In an article by Barry Arkles entitled “Tailoring surfaces withsilanes”, published in CHEMTECH, in December of 1977, pages 766-777, theauthor describes the use of organo silanes to form coatings which impartdesired functional characteristics to an underlying oxide-containingsurface. In particular, the organo silane is represented asR_(n)SiX_((4-n)) where X is a hydrolyzable group, typically halogen,alkoxy, acyloxy, or amine. Following hydrolysis, a reactive silanolgroup is said to be formed which can condense with other silanol groups,for example, those on the surface of siliceous fillers, to form siloxanelinkages. Stable condensation products are said to be formed with otheroxides in addition to silicon oxide, such as oxides of aluminum,zirconium, tin, titanium, and nickel. The R group is said to be anonhydrolyzable organic radical that may possess functionality thatimparts desired characteristics. The article also discusses reactivetetra-substituted silanes which can be fully substituted by hydrolyzablegroups and how the silicic acid which is formed from such substitutedsilanes readily forms polymers such as silica gel, quartz, or silicatesby condensation of the silanol groups or reaction of silicate ions.Tetrachlorosilane is mentioned as being of commercial importance sinceit can be hydrolyzed in the vapor phase to form amorphous fumed silica.

The article by Dr. Arkles shows how a substrate with hydroxyl groups onits surface can be reacted with a condensation product of anorganosilane to provide chemical bonding to the substrate surface. Thereactions are generally discussed and, with the exception of theformation of amorphous fumed silica, the reactions are between a liquidprecursor and a substrate having hydroxyl groups on its surface. Anumber of different applications and potential applications arediscussed.

In an article entitled “Organized Monolayers by Adsorption. 1. Formationand Structure of Oleophobic Mixed Monolayers on Solid Surfaces”,published in the Journal of the American Chemical Society, Jan. 2, 1980,pp. 92-98, Jacob Sagiv discussed the possibility of producing oleophobicmonolayers containing more than one component (mixed monolayers). Thearticle is said to show that homogeneous mixed monolayers containingcomponents which are very different in their properties and molecularshape may be easily formed on various solid polar substrates byadsorption from organic solutions. Irreversible adsorption is said to beachieved through covalent bonding of active silane molecules to thesurface of the substrate.

Rivka Maoz et al., in an article entitled “Self-Assembling Monolayers InThe Construction Of Planned Supramolecular Structures And As ModifiersOf Surface Properties”, Journal de chimie physique, 1988, 85, n° 11/12,describes organized monolayer structures prepared on polar solids viaspontaneous adsorption from organic solutions. The monolayer structuresare covalently bonded to the substrate, which is a solid surface.

In June of 1991, D. J. Ehrlich and J. Melngailis published an articleentitled “Fast room-temperature growth of SiO₂ films by molecular-layerdosing” in Applied Physics Letters 58 (23), pp. 2675-2677. The authorsdescribe a molecular-layer dosing technique for room-temperature growthof α-SiO₂ thin films, which growth is based on the reaction of H₂O andSiCl₄ adsorbates. The reaction is catalyzed by the hydrated SiO₂ growthsurface, and requires a specific surface phase of hydrogen-bonded water.Thicknesses of the films is said to be controlled to molecular-layerprecision; alternatively, fast conformal growth to rates exceeding 100nm/min is said to be achieved by slight depression of the substratetemperature below room temperature. Potential applications such astrench filling for integrated circuits and hermetic ultrathin layers formultilayer photoresists are mentioned. Excimer-laser-induced surfacemodification is said to permit projection-patterned selective-areagrowth on silicon.

An article entitled “Atomic Layer Growth of SiO₂ on Si(100) Using TheSequential Deposition of SiCl₄ and H₂O” by Sneh et al. in Mat. Res. Soc.Symp. Proc. Vol 334, 1994, pp. 25-30, describes a study in which SiO₂thin films were said to be deposited on Si(100) with atomic layercontrol at 600° K (−327° C.) and at pressures in the range of 1 to 50Torr using chemical vapor deposition (CVD).

In an article entitled “SiO₂ Chemical Vapor Deposition at RoomTemperature Using SiCl₄ and H₂O with an NH₃ Catalyst”, by J. W. Klausand S. M. George in the Journal of the Electrochemical Society, 147 (7)2658-2664, 2000, the authors describe the deposition of silicon dioxidefilms at room temperature using a catalyzed chemical vapor depositionreaction. The NH3 (ammonia) catalyst is said to lower the requiredtemperature for SiO₂ CVD from greater than 900° K to about 313-333° K.

Ashurst et al., in an article entitled “Dichlorodimethylsilane as anAnti-Stiction Monolayer for MEMS: A Comparison to theOctadecyltrichlorosilane Self-Assembled Monolayer”, present aquantitative comparison of the dichlorodimethylsilane (DDMS) to theoctadecyltrichlorosilane (OTS) self-assembled monolayer (SAM). Thecomparison is with respect to film properties of the films producedusing these precursor materials and the effectiveness of the films asanti-stiction coatings for micromechanical structures. The coatingdeposition is carried out using iso-octane as the solvent from which theprecursor molecules are deposited.

U.S. Pat. No. 5,328,768 to Goodwin, issued Jul. 12, 1994,. discloses amethod and article wherein a glass substrate is provided with a moredurable non-wetting surface by treatment with a perfluoroalkyl alkylsilane and a fluorinated olefin telomer on a surface which comprises asilica primer layer. The silica primer layer is said to be preferablypyrolytically deposited, magnetron sputtered, or applied by a sol-gelcondensation reaction (i.e. from alkyl silicates or chlorosilanes). Aperfluoroalkyl alkyl silane combined with a fluorinated olefin telomeris said to produce a preferred surface treatment composition. Thesilane/olefin composition is employed as a solution, preferably in afluorinated solvent. The solution is applied to a substrate surface byany conventional technique such as dipping, flowing, wiping, orspraying.

In U.S. Pat. No. 5,372,851, issued to Ogawa et al. on Dec. 13, 1995, amethod of manufacturing a chemically adsorbed film is described. Inparticular a chemically adsorbed film is said to be formed on any typeof substrate in a short time by chemically adsorbing a chlorosilanebased surface active-agent in a gas phase on the surface of a substratehaving active hydrogen groups. The basic reaction by which achlorosilane is attached to a surface with hydroxyl groups present onthe surface is basically the same as described in other articlesdiscussed above. In a preferred embodiment, a chlorosilane basedadsorbent or an alkoxyl-silane based adsorbent is used as thesilane-based surface adsorbent, where the silane-based adsorbent has areactive silyl group at one end and a condensation reaction is initiatedin the gas phase atmosphere. A dehydrochlorination reaction or ade-alcohol reaction is carried out as the condensation reaction. Afterthe dehydrochlorination reaction, the unreacted chlorosilane-basedadsorbent on the surface of the substrate is washed with a non-aqueoussolution and then the adsorbed material is reacted with aqueous solutionto form a monomolecular adsorbed film.

U.S. Patent Publication No. US 2002/0065663 A1, published on May 30,2002, and titled “Highly Durable Hydrophobic Coatings And Methods”,describes substrates which have a hydrophobic surface coating comprisedof the reaction products of a chlorosilyl group containing compound andan alkylsilane. The substrate over which the coating is applied ispreferably glass. In one embodiment, a silicon oxide anchor layer orhybrid organo-silicon oxide anchor layer is formed from a humidifiedreaction product of silicon tetrachloride or trichloromethylsilanevapors at atmospheric pressure. Application of the oxide anchor layeris, followed by the vapor-deposition of a chloroalkylsilane. The siliconoxide anchor layer is said to advantageously have a root mean squaresurface (nm) roughness of less than about 6.0 nm, preferably less thanabout 5.0 nm and a low haze value of less than about 3.0%. The RMSsurface roughness of the silicon oxide layer is preferably said to begreater than about 4 nm, to improve adhesion. However, too great an RMSsurface area is said to result in large surface peaks, widely spacedapart, which begins to diminish the desirable surface area forsubsequent reaction with the chloroalkylsilane by vapor deposition. Toosmall an RMS surface is said to result in the surface being too smooth,that is to say an insufficient increase in the surface area/orinsufficient depth of the surface peaks and valleys on the surface.

Simultaneous vapor deposition of silicon tetrachloride anddimethyldichlorosilane onto a glass substrate is said to result in ahydrophobic coating comprised of cross-linked polydimethylsiloxane whichmay then be capped with a fluoroalkylsilane (to provide hydrophobicity).The substrate is said to be glass or a silicon oxide anchor layerdeposited on a surface prior to deposition of the cross-linkedpolydimethylsiloxane. The substrates are cleaned thoroughly and rinsedprior to being placed in the reaction chamber.

U.S. Patent Publication No. 2003/0180544 A1, published Sep. 25, 2003,and entitled “Anti-Reflective Hydrophobic Coatings and Methods,describes substrates having anti-reflective hydrophobic surfacecoatings. The coatings are typically deposited on a glass substrate. Asilicon oxide anchor layer is formed from a humidified reaction productof silicon tetrachloride, followed by the vapor deposition of achloroalkylsilane. The thickness of the anchor layer and the overlayerare said to be such that the coating exhibits light reflectance of lessthan about 1.5%. The coatings are said to be comprised of the reactionproducts of a vapor-deposited chlorosilyl group containing compound anda vapor-deposited alkylsilane.

U.S. Pat. No. 6,737,105, issued May 18, 2004 to David A. Richard, andentitled “Multilayered Hydrophobic Coating And Method Of ManufacturingThe Same”, describes a multi-layer coating for a transparent substrate,where the coating increases durability and weatherability of thesubstrate. The coating includes a surface-hardening layer oforgano-siloxane formed over the substrate. An abrasion-resistant coatingcomprising a multi-layer stack of alternating layers of silicon dioxideand zirconium dioxide is formed over the surface-hardening layer. Themulti-layer coating further includes a hydrophobic outer layer ofperfluoroalkylsilane formed over the abrasion-resistant coating. Theorgano-silicon surface hardening layer is said to be sprayed, dipped, orcentrifugally coated onto the substrate. The abrasion-resistant coatingand the hydrophobic layer are said to be applied using any known drycoating technique, such as vacuum deposition or ion assisted deposition,with no process details provided.

Related references which pertain to coatings deposited on a substratesurface from a vapor include the following, as examples and not by wayof limitation, U.S. Pat. No. 5,576,247 to Yano et al., issued Nov. 19,1996, entitled: “Thin layer forming method where hydrophobic molecularlayers preventing a BPSG layer from absorbing moisture”. U.S. Pat. No.5,602,671 of Hornbeck, issued February 11, 1997, which describes lowsurface energy passivation layers for use in micromechanical devices. Anarticle entitled “Vapor phase deposition of uniform and ultrathinsilanes”, by Yuchun Wang et al., SPIE Vol. 3258-0277-786X(98) 20-28, inwhich the authors describe uniform, conformal, and ultrathin coatingsneeded on the surface of biomedical microdevices such as microfabricatedsilicon filters, in order to regulate hydrophilicity and to minimizeunspecific protein adsorption. Jian Wang et al., in an article publishedin Thin Solid Films 327-329 (1998) 591-594, entitled: “Goldnanoparticulate film bound to silicon surface with self-assembledmonolayers”, discuss a method for attaching gold nanoparticles tosilicon surfaces with a self aligned monolayer (SAM) used for surfacepreparation“.

Patrick W. Hoffmann et al., in an article published by the AmericanChemical Society, Langmuir 1997, 13, 1877-1880, describe the surfacecoverage and molecular orientation of monomolecular thin organic filmson a Ge/Si oxide substrate. A gas phase reactor was said to have beenused to provide precise control of substrate surface temperature and gasflow rates during deposition of monofunctional perfluoratedalkylsilanes. Complete processing conditions are not provided, and thereis no description of the apparatus which was used to apply the thinfilms. T. M. Mayer et al. describe a “Chemical vapor deposition offluoroalkylsilane monolayer films for adhesion control inmicroelectromechanical systems” in J. Vac. Sci. Technol. B 18(5),September/October 2000. This article mentions the use of a remotelygenerated microwave plasma for cleaning a silicon substrate surfaceprior to film deposition, where the plasma source gas is either watervapor or oxygen.

U.S. Pat. No. 6,576,489 to Leung et al., issued Jun. 10, 2003 describesmethods of forming microstructure devices. The methods include the useof vapor-phase alkylsilane-containing molecules to form a coating over asubstrate surface. The alkylsilane-containing molecules are introducedinto a reaction chamber containing the substrate by bubbling ananhydrous, inert gas through a liquid source of thealkylsilane-containing molecules, and transporting the molecules withthe carrier gas into the reaction chamber. The formation of the coatingis carried out on a substrate surface at a temperature ranging betweenabout 15° C. and 100° C., at a pressure in the reaction chamber which issaid to be below atmospheric pressure, and yet sufficiently high for asuitable amount of alkylsilane-containing molecules to be present forexpeditious formation of the coating.

Some of the various methods useful in applying layers and coatings to asubstrate have been described above. There are numerous other patentsand publications which relate to the deposition of functional coatingson substrates, but which appear to us to be more distantly related tothe present invention. However, upon reading these informativedescriptions, it becomes readily apparent that control of coatingdeposition on a molecular level is not addressed in adequate detail.When this is discussed, the process is typically described ingeneralized terms like those mentioned directly above, which terms arenot enabling to one skilled in the art, but merely suggestexperimentation. To provide a multilayered functional coating on asubstrate surface which exhibits functional features on a nanometerscale, it is necessary to tailor the coating precisely. Without precisecontrol of the deposition process, the coating may lack thicknessuniformity and surface coverage, providing a rough surface. Or, thecoating may vary in chemical composition across the surface of thesubstrate. Or, the coating may differ in structural composition acrossthe surface of the substrate. Any one of these non-uniformities mayresult in functional discontinuities and defects on the coated substratesurface which are unacceptable for the intended application of thecoated substrate.

U.S. patent application Ser. No. 10/759,857 of the present applicantsdescribes processing apparatus which can provide specificallycontrolled, accurate delivery of precise quantities of reactants to theprocess chamber, as a means of improving control over a coatingdeposition process. The subject matter of the '857 application is herebyincorporated by reference in its entirety. The focus of the presentapplication is the control of process conditions in the reaction chamberin a manner which, in combination with delivery of accurate quantitiesof reactive materials, provides a uniform, functional multilayeredcoating on a nanometer scale. The multilayered coating exhibitssufficient uniformity of thickness, chemical composition and structuralcomposition over the substrate surface that such nanometer scalefunctionality is achieved. Further, particular multilayered structuresprovide an unexpected improvement in physical properties over coatingsknown in the art.

SUMMARY OF THE INVENTION

We have developed a series of multilayered coatings which are tailoredto provide particular thickness, mechanical properties and surfaceproperty characteristics. Preferably, but not by way of limitation, themultilayered coatings include sequentially applied layers which areapplied using MOLECULAR VAPOR DEPOSITION™ (MVD) (AppliedMicroStructures, Inc., San Jose, Calif.) techniques. The MVD depositionmethod is a vapor-phase deposition method which employs carefullycontrolled amounts of precursor reagents. Typically a stagnationreaction from carefully controlled amounts of precursor reagents isemployed. However, it is possible to use other methods of vapor-phasedeposition for coating layer application, such as a continuous gas flowtechnique of the kind which is known in the art, where our techniquesfor accurate control over amounts of precursor reagents are employed.

The MVD deposition method is carried out using an apparatus whichenables a stepped addition and mixing of all of the reactants to beconsumed in a given process step, whether that process step is one in aseries of steps or is the sole step in a coating formation process. Insome instances, the coating formation process may include a number ofindividual steps where repetitive reactive processes are carried out ineach individual step. The coating process may also include plasmatreatment of the surface of one deposited layer prior to application ofan overlying layer. Typically the plasma used for such treatment is alow density plasma. This plasma may be a remotely-generated plasma. Themost important feature of the plasma treatment is that it is a “soft”plasma which affects the exposed surface enough to activate the surfaceof the layer being treated, but not enough to etch through the layer.The apparatus used to carry out the method provides for the addition ofa precise amount of each of the reactants to be consumed in a singlereaction step of the coating formation process. The apparatus mayprovide for precise addition of quantities of different combinations ofreactants during each individual step when there are a series ofdifferent individual steps in the coating formation process. Some of theindividual steps may be repetitive.

In addition to the control over the amount of reactants added to theprocess chamber, the present invention requires precise control over thecleanliness of the substrate, the order of reactant(s) introduction, thetotal pressure (which is typically less than atmospheric pressure) inthe process chamber, the partial vapor pressure of each vaporouscomponent present in the process chamber, the temperature of thesubstrate and chamber walls, and the amount of time that a given set ofconditions is maintained. The control over this combination of variablesdetermines the deposition rate and properties of the deposited layers.By varying these process parameters, we control the amount of thereactants available, the density of reaction sites, and the film growthrate, which is the result of the balance of the competitive adsorptionand desorption processes on the substrate surface, as well as any gasphase reactions.

Typically, the total pressure in the process chamber is lower thanatmospheric pressure and the partial pressure of each vaporous componentmaking up the reactive mixture is specifically controlled so thatformation and attachment of molecules on a substrate surface are wellcontrolled processes that can take place in a predictable manner. Thesubstrate surface concentration and location of reactive species arecontrolled using total pressure in the processing chamber, the kind andnumber of vaporous components present in the process chamber, and thepartial pressure of each vaporous component in the chamber, for example.To obtain the planned reaction on the initial, uncoated substratesurface, the initial substrate surface has to be prepared so that thereactivity of the surface itself with the vaporous components present inthe process chamber will be as expected. The treatment may be a wetchemical clean, but is preferably a plasma treatment. Typicallytreatment with an oxygen plasma removes common surface contaminants. Insome instances, it is necessary not only to remove contaminants from thesubstrate surface, but also to generate —OH functional groups on thesubstrate surface (in instances where such —OH functional groups are notalready present).

The surface properties of a multilayered structure may be controlled bythe method of the invention. The hydrophobicity of a given substratesurface may be measured using a water droplet shape analysis method, forexample. Silicon substrates, when treated with oxygen-containingplasmas, can be freed from organic contaminants and typically exhibit awater contact angle below 10°, indicative of a hydrophilic property ofthe treated substrate. In the case of more hydrophobic substrates, suchas, for example, plastics or metals, the deposition or creation of anoxide-based layer or a nitride-based layer on the substrate surface maybe used to alter the hydrophobicity of the substrate surface. An oxidelayer is typically preferred due to the ease of creating an oxide layer.The oxide layer may comprise aluminum oxide, titanium oxide, or siliconoxide, by way of example and not by way of limitation. When the oxidelayer is aluminum or titanium oxide, or when the layer is anitride-based layer, an auxiliary process chamber (to the processchamber described herein) may be used to create this oxide layer ornitride layer. When the oxide layer is a silicon oxide layer, thesilicon oxide layer may be applied by an embodiment method of thepresent invention which is described in detail herein, to provide a morehydrophilic substrate surface in the form of an oxide-based bondinglayer comprising —OH functional groups. For example, an oxide surfaceprepared by the method can be used to adjust surface hydrophobicitydownward to be as low as 5 degrees, rendering the surface hydrophilic.

Where it is desired to have a particularly uniform growth of thecomposition across the coating surface, or a variable composition acrossthe thickness of a multilayered coating, more than one batch ofreactants may be charged to the process chamber during formation of thecoating.

The coatings formed by the method of the invention can be sufficientlycontrolled so that the surface roughness of the coating in terms of RMSis less than about 10 nm, and is typically in the range of about 0.5 nmto 5 nm.

One example of the application of the method described here isdeposition of a multilayered coating including at least one oxide-basedlayer. The thickness of the oxide-based layer depends on the end-useapplication for the multilayered coating. The oxide-based layer (or aseries of oxide-based layers alternated with organic-based layers) maybe used to increase the overall thickness of the multilayered coating(which typically derives the majority of its thickness from theoxide-based layer), and depending on the mechanical properties to beobtained, the oxide-based layer content of the multilayered coating maybe increased when more coating rigidity and abrasion resistance isrequired.

The oxide-based layer is frequently used to provide a bonding surfacefor subsequently deposited various molecular organic-based coatinglayers. When the surface of the oxide-based layer is one containing -OHfunctional groups, the organic-based coating layer typically includes,for example and not by way of limitation, a silane-based functionalitywhich permits covalent bonding of the organic-based coating layer to —OHfunctional groups present on the surface of the oxide-based layer. Whenthe surface of the oxide-based layer is one capped with halogenfunctional groups, such as chlorine, by way of example and not by way oflimitation, the organic-based coating layer includes, for example, an—OH functional group, which permits covalent bonding of theorganic-based coating layer to the oxide-based layer functional halogengroup.

By controlling the precise thickness, chemical, and structuralcomposition of an oxide-based layer on a substrate, for example, we areable to direct the coverage and the functionality of a coating appliedover the bonding oxide layer. The coverage and functionality of thecoating can be controlled over the entire substrate surface on a nmscale. Specific, different thicknesses of an oxide-based substratebonding layer are required on different substrates. Some substratesrequire an alternating series of oxide-based/organic-based layers toprovide surface stability for a coating structure.

With respect to substrate surface properties, such as hydrophobicity orhydrophilicity, for example, a silicon wafer surface becomeshydrophilic, to provide a less than 5 degree water contact angle, afterplasma treatment when there is some moisture present. Not much moistureis required, for example, typically the amount of moisture present afterpumping a chamber from ambient air down to about 15 mTorr to 20 mTorr issufficient moisture. A stainless steel surface requires formation of anoverlying oxide-based layer having a thickness of about 30 Å or more toobtain the same degree of hydrophilicity as that obtained by plasmatreatment of a silicon surface. Glass and polystyrene materials becomehydrophilic, to a 5 degree water contact angle, after the application ofabout 80 Å or more of an oxide-based layer. An acrylic surface requiresabout 150 Å or more of an oxide-based layer to provide a 5 degree watercontact angle.

There is also a required thickness of oxide-based layer to provide agood bonding surface for reaction with a subsequently appliedorganic-based layer. By a good bonding surface, it is meant a surfacewhich provides full, uniform surface coverage of the organic-basedlayer. By way of example, about 80 Å or more of a oxide-based substratebonding layer over a silicon wafer substrate provides a uniformhydrophobic contact angle, about 112 degrees, upon application of a SAMorganic-based layer deposited from an FDTS(perfluorodecyltrichlorosilanes) precursor. About 150 Å or more ofoxide-based substrate bonding layer is required over a glass substrateor a polystyrene substrate to obtain a uniform coating having a similarcontact angle. About 400 Å or more of oxide-based substrate bondinglayer is required over an acrylic substrate to obtain a uniform coatinghaving a similar contact angle.

The organic-based layer precursor, in addition to containing afunctional group capable of reacting with the oxide-based layer toprovide a covalent bond, may also contain a functional group at alocation which will form the exterior surface of the attachedorganic-based layer. This functional group may subsequently be reactedwith other organic-based precursors, or may be the final layer of thecoating and be used to provide surface properties of the coating, suchas to render the surface hydrophobic or hydrophilic, by way of exampleand not by way of limitation. The functionality of an attachedorganic-based layer may be affected by the chemical composition of theprevious organic-based layer (or the chemical composition of the initialsubstrate) if the thickness of the oxide layer separating the attachedorganic-based layer from the previous organic-based layer (or othersubstrate) is inadequate. The required oxide-based layer thickness is afunction of the chemical composition of the substrate surface underlyingthe oxide-based layer, as illustrated above. In some instances, toprovide structural stability for the surface layer of the coating, it isnecessary to apply several alternating layers of an oxide-based layerand an organic-based layer.

With reference to chlorosilane-based coating systems of the kinddescribed in the Background Art section of this application, where oneend of the organic molecule presents chlorosilane, and the other end ofthe organic molecule presents a fluorine moiety, after attachment of thechlorosilane end of the organic molecule to the substrate, the fluorinemoiety at the other end of the organic molecule provides a hydrophobiccoating surface. Further, the degree of hydrophobicity and theuniformity of the hydrophobic surface at a given location across thecoated surface may be controlled using the oxide-based layer which isapplied over the substrate surface prior to application of thechlorosilane-comprising organic molecule. By controlling the oxide-basedlayer application, the organic-based layer is controlled indirectly. Forexample, using the process variables previously described, we are ableto control the concentration of OH reactive species on the substratesurface. This, in turn, controls the density of reaction sites neededfor subsequent deposition of a silane-based polymeric coating. Controlof the substrate surface active site density enables uniform growth andapplication of high density self-aligned monolayer coatings (SAMS), forexample.

We have discovered that it is possible to convert a hydrophilic-likesubstrate surface to a hydrophobic surface by application of anoxide-based layer of the minimal thickness described above with respectto a given substrate, followed by application of an organic-based layerover the oxide-based layer, where the organic-based layer provideshydrophobic surface functional groups on the end of the organic moleculewhich does not react with the oxide-based layer. However, when theinitial substrate surface is a hydrophobic surface and it is desired toconvert this surface to a hydrophilic surface, it is necessary to use astructure which comprises more than one oxide-based layer to obtainstability of the applied hydrophilic surface in water. It is not justthe thickness of the oxide-based layer or the thickness of theorganic-based layer which is controlling. The structural stabilityprovided by a multilayered structure of repeated layers of oxide-basedmaterial interleaved with organic-based layers provides excellentresults.

By controlling the total pressure in the vacuum processing chamber, thenumber and kind of vaporous components charged to the process chamber,the relative partial pressure of each vaporous component, the substratetemperature, the temperature of the process chamber walls, and the timeover which particular conditions are maintained, the chemical reactivityand properties of the coating can be controlled. By controlling theprocess parameters, both density of film coverage over the substratesurface and structural composition over the substrate surface are moreaccurately controlled, enabling the formation of very smooth films,which typically range from about 0.1 nm to less than about 5 nm, andeven more typically from about 1 nm to about 3 nm in surface RMSroughness. The thickness of smooth (RMS=5 nm or less) oxide bondinglayer films typically ranges from about 0.5 nm to about 15 nm. Thesesmooth films can be tailored in thickness, roughness, hydrophilicity,and density, which makes them particularly well suited for applicationsin the field of biotechnology and electronics and as bonding layers forvarious functional coatings in general.

After deposition of a first organic-based layer, and prior to thedeposition of an overlying layer in a multilayered coating, it isadvisable to use an in-situ oxygen plasma treatment. This treatmentactivates reaction sites of the first organic-based layer and may beused as part of a process for generating an oxide-based layer or simplyto activate dangling bonds on the substrate surface. The activateddangling bonds may be exploited to provide reactive sites on thesubstrate surface. For example, an oxygen plasma treatment incombination with a controlled partial pressure of water vapor may beused to create a new concentration of OH reactive species on an exposedsurface. The activated surface is then used to provide covalent bondingwith the next layer of material applied. A deposition process may thenbe repeated, increasing the total coating thickness, and eventuallyproviding a surface layer having the desired surface properties. In someinstances, where the substrate surface includes metal atoms, treatmentwith the oxygen plasma and moisture provides a metal oxide-based layercontaining —OH functional groups. This oxide-based layer is useful forincreasing the overall thickness of the multilayered coating and forimproving mechanical strength and rigidity of the multilayered coating.

By changing the total pressure in the process chamber and/or limitingthe partial pressure of a reactive vaporous component so that thecomponent is “starved” from the reactive substrate surface, thecomposition of the depositing coating can be “dialed in” to meetparticular requirements.

A computer driven process control system may be used to provide for aseries of additions of reactants to the process chamber in which thelayer or coating is being formed. This process control system typicallyalso controls other process variables, such as, (for example and not byway of limitation), total process chamber pressure (typically less thanatmospheric pressure), substrate temperature, temperature of processchamber walls, temperature of the vapor delivery manifolds, processingtime for given process steps, and other process parameters if needed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-sectional schematic of one embodiment of the kindof an apparatus which can be used to carry out a vapor deposition of acoating in accordance with the method of the present invention.

FIG. 2 is a schematic which shows the reaction mechanism wheretetrachlorosilane and water are reacted with a substrate which exhibitsactive hydroxyl groups on the substrate surface, to form a silicon oxidelayer on the surface of the substrate.

FIGS. 3A and 3B show schematics of atomic force microscope (AFM) imagesof silicon oxide bonding layers deposited on a silicon substrate. Theinitial silicon substrate surface RMS roughness measured less than about0.1 nm.

FIG. 3A shows the schematic for an AFM picture of a 4 nm thick siliconoxide bonding layer deposited from SiCl₄ precursor using the method ofthe present invention, where the RMS roughness is about 1.4 nm.

FIG. 3B shows the schematic for an AFM picture of a 30 nm thick siliconoxide bonding layer deposited from SiCl₄ precursor using the method ofthe present invention, where the RMS roughness is about 4.2 nm.

FIG. 4 shows a graph of the water contact angle obtained on a siliconsubstrate surface as a function of reaction time (exposure time to DDMSand H₂O reactants) during coating formation.

FIG. 5 shows a series of water contact angles measured for a coatingsurface where the coating was produced from a FOTS precursor on thesurface of a silicon substrate. The higher the contact angle, the higherthe hydrophobicity of the coating surface.

FIG. 6A shows a three dimensional plot of film thickness of a siliconoxide bonding layer coating deposited on a silicon surface as a functionof the partial pressure of silicon tetrachloride and the partialpressure of water vapor present in the process chamber during depositionof the silicon oxide coating, where the time period the siliconsubstrate was exposed to the coating precursors was four minutes aftercompletion of addition of all precursor materials.

FIG. 6B shows a three dimensional plot of film thickness of the siliconoxide bonding layer illustrated in FIG. 6A as a function of the watervapor partial pressure and the time period the substrate was exposed tothe coating precursors after completion of addition of all precursormaterials.

FIG. 6C shows a three dimensional plot of film thickness of the siliconoxide bonding layer illustrated in FIG. 6A as a function of the silicontetrachloride partial pressure and the time period the substrate wasexposed to the coating precursors after completion of addition of allprecursor materials.

FIG. 7A shows a three dimensional plot of film roughness in RMS nm of asilicon oxide bonding layer coating deposited on a silicon surface as afunction of the partial pressure of silicon tetrachloride and thepartial pressure of water vapor present in the process chamber duringdeposition of the silicon oxide coating, where the time period thesilicon substrate was exposed to the coating precursors was four minutesafter completion of addition of all precursor materials.

FIG. 7B shows a three dimensional plot of film roughness in RMS nm ofthe silicon oxide bonding layer illustrated in FIG. 7A as a function ofthe water vapor partial pressure and the time period the substrate wasexposed to the coating precursors after completion of addition of allprecursor materials.

FIG. 7C shows a three dimensional plot of film roughness in RMS nm ofthe silicon oxide bonding layer illustrated in FIG. 6A as a function ofthe silicon tetrachloride partial pressure and the time period thesubstrate was exposed to the coating precursors after completion ofaddition of all precursor materials.

FIG. 8A illustrates the change in hydrophilicity of the surface of theinitial substrate as a function of the thickness of an oxide-basedbonding layer generated over the initial substrate surface using anoxygen plasma, moisture, and carbon tetrachloride. When the oxidethickness is adequate to provide full coverage of the substrate surface,the contact angle on the surface drops to about 5 degrees or less.

FIG. 8B illustrates the minimal thickness of oxide-based bonding layerwhich is required to provide adhesion of an organic-based layer, as afunction of the initial substrate material, when the organic-based layeris one where the end or the organic-based layer which bonds to theoxide-based bonding layer is a silane and where the end of theorganic-based layer which does not bond to the oxide-based bonding layerprovides a hydrophobic surface. When the oxide thickness is adequate toprovide uniform attachment of the organic-based layer, the contact angleon the substrate surface increases to about 110 degrees or greater.

FIG. 9A shows stability in DI water for an organic-based self-aligningmonolayer (SAM) generated from perfluorodecyltrichloro-silane (FDTS)applied over a silicon wafer surface; and, applied over a 150 Å thickoxide-based layer, or applied over a 400 Å thick oxide-based layer,where the initial substrate surface is a silicon wafer. For a siliconsubstrate (which provides a hydrophilic surface) the stability of theorganic-based layer, in terms of the hydrophobic surface provided, isrelatively good for each of the samples, and somewhat better for thetest specimens where there is an oxide-based layer underlying theorganic-based layer.

FIG. 9B shows stability in DI water for the same organic-basedFDTS-generated SAM layer applied over the same oxide-based layers, wherethe initial substrate surface is polystyrene. There is minimal directbonding of the organic-based layer to the polystyrene substrate.Initially, there is bonding of the organic-based layer to thepolystyrene substrate, but the bonding fails relatively rapidly, so thatthe hydrophobic surface properties are lost.

FIG. 9C shows stability in DI water for the same organic-basedFDTS-generated SAM layer applied over the same two different thicknessesof an oxide-based layer as those shown in FIG. 9A, where the initialsubstrate surface is acrylic. Also shown is the improvement in long termreliability and performance when a series of five pairs of oxide-basedlayer/organic-based layer are applied over the acrylic substratesurface.

FIGS. 10A-10B show the use of a multilayered coating of one embodimentof the present invention, where the coating is used to increase theaspect ratio of a nozzle (shown in FIG. 10A) or an orifice (shown inFIG. 10B), while providing particular surface properties on the coatedsurfaces.

FIG. 11A illustrates the improvement in DI water stability of anothermultilayered coating, where the organic-based precursor wasfluoro-tetrahydrooctyldimethylchlorosilanes (FOTS). The surfacestability of a FOTS organic-based layer applied directly over thesubstrate surface is compared with the surface stability of a FOTSorganic-based layer, which is the upper surface layer of a series ofalternating layers of oxide-based layer followed by organic based layer.FIG. 11A shows data for a silicon substrate surface.

FIG. 11B shows the same kind of comparison as shown in FIG. 11A;however, the substrate is glass.

FIG. 11C shows comparative data for the five pairs oxide-basedlayer/organic-based layer structures of the kind described with respectto FIG. 11A, where the substrate is silicon; however, the stability datais for temperature rather than for exposure to DI water. The contactangle is shown after a number of hours at 250° C.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

As a preface to the detailed description, it should be noted that, asused in this specification and the appended claims, the singular forms“a”, “an”, and “the” include plural referents, unless the contextclearly dictates otherwise.

As a basis for understanding the invention, it is necessary to discussthe processing apparatus which permits precise control over the additionof coating precursors and other vaporous components present within thereaction/processing chamber in which the coating is applied. Theapparatus described below is not the only apparatus in which the presentinvention may be practiced, it is merely an example of one apparatuswhich may be used. One skilled in the art will recognize equivalentelements in other forms which may be substituted and still provide anacceptable processing system.

I. An Apparatus for Vapor Deposition of the Thin Coatings

FIG. 1 shows a cross-sectional schematic of an apparatus 100 for vapordeposition of thin coatings. The apparatus 100 includes a processchamber 102 in which thin (typically 0.5 mn to 50 nm thick) coatings arevapor deposited. A substrate 106 to be coated rests upon a temperaturecontrolled substrate holder 104, typically within a recess 107 in thesubstrate holder 104.

Depending on the chamber design, the substrate 106 may rest on thechamber bottom (not shown in this position in FIG. 1). Attached toprocess chamber 102 is a remote plasma source 110, connected via a valve108. Remote plasma source 110 may be used to provide a plasma which isused to clean and/or convert a substrate surface to a particularchemical state prior to application of a coating (which enables reactionof coating species and/or catalyst with the surface, thus improvingadhesion and/or formation of the coating); or may be used to providespecies helpful during formation of the coating (not shown) ormodifications of the coating after deposition. The plasma may begenerated using a microwave, DC, or inductive RF power source, orcombinations thereof. The process chamber 102 makes use of an exhaustport 112 for the removal of reaction byproducts and is opened forpumping/purging the chamber 102. A shut-off valve or a control valve 114is used to isolate the chamber or to control the amount of vacuumapplied to the exhaust port. The vacuum source is not shown in FIG. 1.

The apparatus 100 shown in FIG. 1 is illustrative of a vapor depositedcoating which employs two precursor materials and a catalyst. Oneskilled in the art will understand that one or more precursors and fromzero to multiple catalysts may be used during vapor deposition of acoating. A catalyst storage container 116 contains catalyst 154, whichmay be heated using heater 118 to provide a vapor, as necessary. It isunderstood that precursor and catalyst storage container walls, andtransfer lines into process chamber 102 will be heated as necessary tomaintain a precursor or catalyst in a vaporous state, minimizing oravoiding condensation. The same is true with respect to heating of theinterior surfaces of process chamber 102 and the surface of substrate106 to which the coating (not shown) is applied. A control valve 120 ispresent on transfer line 119 between catalyst storage container 116 andcatalyst vapor reservoir 122, where the catalyst vapor is permitted toaccumulate until a nominal, specified pressure is measured at pressureindicator 124. Control valve 120 is in a normally-closed position andreturns to that position once the specified pressure is reached incatalyst vapor reservoir 122. At the time the catalyst vapor in vaporreservoir 122 is to be released, valve 126 on transfer line 119 isopened to permit entrance of the catalyst present in vapor reservoir 122into process chamber 102 which is at a lower pressure. Control valves120 and 126 are controlled by a programmable process control system ofthe kind known in the art (which is not shown in FIG. 1).

A Precursor 1 storage container 128 contains coating reactant Precursor1, which may be heated using heater 130 to provide a vapor, asnecessary. As previously mentioned, Precursor 1 transfer line 129 andvapor reservoir 134 internal surfaces are heated as necessary tomaintain a Precursor 1 in a vaporous state, minimizing and preferablyavoiding condensation. A control valve 132 is present on transfer line129 between Precursor 1 storage container 128 and Precursor 1 vaporreservoir 134, where the Precursor 1 vapor is permitted to accumulateuntil a nominal, specified pressure is measured at pressure indicator136. Control valve 132 is in a normally-closed position and returns tothat position once the specified pressure is reached in Precursor 1vapor reservoir 134. At the time the Precursor 1 vapor in vaporreservoir 134 is to be released, valve 138 on transfer line 129 isopened to permit entrance of the Precursor 1 vapor present in vaporreservoir 134 into process chamber 102, which is at a lower pressure.Control valves 132 and 138 are controlled by a programmable processcontrol system of the kind known in the art (which is not shown in FIG.1).

A Precursor 2 storage container 140 contains coating reactant Precursor2, which may be heated using heater 142 to provide a vapor, asnecessary. As previously mentioned, Precursor 2 transfer line 141 andvapor reservoir 146 internal surfaces are heated as necessary tomaintain Precursor 2 in a vaporous state, minimizing, and preferablyavoiding condensation. A control valve 144 is present on transfer line141 between Precursor 2 storage container 146 and Precursor 2 vaporreservoir 146, where the Precursor 2 vapor is permitted to accumulateuntil a nominal, specified pressure is measured at pressure indicator148. Control valve 141 is in a normally-closed position and returns tothat position once the specified pressure is reached in Precursor 2vapor reservoir 146. At the time the Precursor 2 vapor in vaporreservoir 146 is to be released, valve 150 on transfer line 141 isopened to permit entrance of the Precursor 2 vapor present in vaporreservoir 146 into process chamber 102, which is at a lower pressure.Control valves 144 and 150 are controlled by a programmable processcontrol system of the kind known in the art (which is not shown in FIG.1).

During formation of a coating (not shown) on a surface 105 of substrate106, at least one incremental addition of vapor equal to the vaporreservoir 122 of the catalyst 154, and the vapor reservoir 134 of thePrecursor 1, or the vapor reservoir 146 of Precursor 2 may be added toprocess chamber 102. The total amount of vapor added is controlled byboth the adjustable volume size of each of the expansion chambers(typically 50 cc up to 1,000 cc) and the number of vapor injections(doses) into the reaction chamber. Further, the set pressure 124 forcatalyst vapor reservoir 122, or the set pressure 136 for Precursor 1vapor reservoir 134, or the set pressure 148 for Precursor 2 vaporreservoir 146, may be adjusted to control the amount (partial vaporpressure) of the catalyst or reactant added to any particular stepduring the coating formation process. This ability to control preciseamounts of catalyst and vaporous precursors to be dosed (charged) to theprocess chamber 102 at a specified time provides not only accuratedosing of reactants and catalysts, but repeatability in the vaporcharging sequence.

This apparatus provides a relatively inexpensive, yet accurate method ofadding vapor phase precursor reactants and catalyst to the coatingformation process, despite the fact that many of the precursors andcatalysts are typically relatively non-volatile materials. In the past,flow controllers were used to control the addition of various reactants;however, these flow controllers may not be able to handle some of theprecursors used for vapor deposition of coatings, due to the low vaporpressure and chemical nature of the precursor materials. The rate atwhich vapor is generated from some of the precursors is generally tooslow to function with a flow controller in a manner which providesavailability of material in a timely manner for the vapor depositionprocess.

The apparatus discussed above allows for accumulation of the specificquantity of vapor in the vapor reservoir which can be charged (dosed) tothe reaction. In the event it is desired to make several doses duringthe coating process, the apparatus can be programmed to do so, asdescribed above. Additionally, adding of the reactant vapors into thereaction chamber in controlled aliquots (as opposed to continuous flow)greatly reduces the amount of the reactants used and the cost of thecoating.

One skilled in the art of chemical processing of a number of substratessimultaneously will recognize that a processing system which permitsheat and mass transfer uniformly over a number of substrate surfacessimultaneously may be used to carry out the present invention.

II. Exemplary Embodiments of the Method of the Invention

A method of the invention provides for vapor-phase deposition ofcoatings, where a processing chamber of the kind, or similar to theprocessing chamber described above is employed. Each coating precursoris transferred in vaporous form to a precursor vapor reservoir in whichthe precursor vapor accumulates. A nominal amount of the precursorvapor, which is the amount required for a coating layer deposition isaccumulated in the precursor vapor reservoir. The at least one coatingprecursor is charged from the precursor vapor reservoir into theprocessing chamber in which a substrate to be coated resides. In someinstances at least one catalyst vapor is added to the process chamber inaddition to the at least one precursor vapor, where the relativequantities of catalyst and precursor vapors are based on the physicalcharacteristics to be exhibited by the coating. In some instances adiluent gas is added to the process chamber in addition to the at leastone precursor vapor (and optional catalyst vapor). The diluent gas ischemically inert and is used to increase a total desired processingpressure, while the partial pressure amounts of coating precursors andoptionally catalyst components are varied.

The example embodiments described below are with reference to thebonding oxide and the silane-based polymeric coating systems of the kindmentioned above. However, it is readily apparent to one of skill in theart that the concepts involved can be applied to additional coatingcompositions and combinations which have different functionalities.

Due to the need to control the degree and scale of functionality of thecoating at dimensions as small as nanometers, the surface preparation ofthe substrate prior to application of the coating is very important. Onemethod of preparing the substrate surface is to expose the surface to auniform, non-physically-bombarding plasma which is typically createdfrom a plasma source gas containing oxygen. The plasma may be a remotelygenerated plasma which is fed into a processing chamber in which asubstrate to be coated resides. Depending on the coating to be applieddirectly over the substrate, the plasma treatment of the substratesurface may be carried out in the chamber in which the coating is to beapplied. This has the advantage that the substrate is easily maintainedin a controlled environment between the time that the surface is treatedand the time at which the coating is applied. Alternatively, it ispossible to use a large system which includes several processingchambers and a centralized transfer chamber which allows substratetransfer from one chamber to another via a robot handling device, wherethe centralized handling chamber as well as the individual processingchambers are each under a controlled environment.

When a silicon oxide layer is applied to the substrate surface toprovide a substrate surface having a controlled hydrophobicity (acontrolled availability of reactive hydroxylated sites), the oxide layermay be created using the well-known catalytic hydrolysis of achlorosilane, such as a tetrachlorosilane, in the manner previouslydescribed. A subsequent attachment of an organo-chlorosilane, which mayor may not include a functional moiety, may be used to impart aparticular function to the finished coating. By way of example and notby way of limitation, the hydrophobicity or hydrophilicity of thecoating surface may be altered by the functional moiety present on asurface of the organo-chlorosilane which becomes an exterior surface ofthe coating.

As previously mentioned, the layer used as an adhering layer in contactwith the substrate surface or in contact with an activated organic-basedlayer may be an oxide-based layer or a nitride-based layer. Anoxide-based layer is described here because to ease of application inthe apparatus described herein. Application of a nitride-based layertypically requires an auxiliary processing chamber designed forapplication of a nitride-based layer, using techniques which aregenerally known in the art. An oxide-based layer, which may be a siliconoxide or another oxide, may be formed using the method of the presentinvention by vapor phase hydrolysis of the chlorosilane, with subsequentattachment of the hydrolyzed silane to the substrate surface.Alternatively, the hydrolysis reaction may take place directly on thesurface of the substrate, where moisture has been made available on thesubstrate surface to allow simultaneous hydrolyzation and attachment ofthe chlorosilane to the substrate surface. The hydrolysis in the vaporphase using relatively wide range of partial pressure of the silicontetrachloride precursor in combination with a partial pressure in therange of 10 Torr or greater of water vapor will generally result inrougher surfaces on the order of 5 nm RMS or greater, where thethickness of the film formed will typically be in the range of about 15nm or greater.

Multi-layer films where at least two oxide-based layers and at least twoorganic-based layers are present, typically have a film thicknessranging from about 7 nm (70 Å) to about 1 μm.

A thin film of an oxide-based layer, prepared on a silicon substrate,where the oxide-based layer exhibits a thickness ranging from about 2 nmto about 15 nm, typically exhibits a 1-5 nm RMS finish. These films aregrown by carefully balancing the vapor and surface hydrolysis reactioncomponents. For example, and not by way of limitation, we have obtainedfilms having a 1-5 nm RMS finish in an apparatus of the kind previouslydescribed, where the partial pressure of the silicon tetrachloride is inthe range of about 0.5 to 4.0 Torr, the partial pressure of the watervapor is in the range of about 2 to about 8 Torr, where the totalprocess chamber pressure ranges from about 3 Torr to about 10 Torr,where the substrate temperature ranges from about 20° C. to about 60°C., where the process chamber walls are at a temperature ranging fromabout 30° C. to about 60° C., and where the time period over which thesubstrate is exposed to the combination of silicon tetrachloride andwater vapor ranges from about 2 minutes to about 12 minutes. Thisdeposition process will be described in more detail subsequently herein,with reference to FIGS. 6A through 6C.

EXAMPLE ONE

Deposition of a Silicon Oxide Layer Having a Controlled Number of OHReactive Sites Available On the Oxide Layer Surface

A technique for adjusting the hydrophobicity/hydrophilicity of asubstrate surface (so that the surface is converted from hydrophobic tohydrophilic or so that a hydrophilic surface is made more hydrophilic,for example) may also be viewed as adjusting the number of OH reactivesites available on the surface of the substrate. One such technique isto apply an oxide coating over the substrate surface while providing thedesired concentration of OH reactive sites available on the oxidesurface. A schematic 200 of the mechanism of oxide formation in shown inFIG. 2. In particular, a substrate 202 has OH groups 204 present on thesubstrate surface 203. A chlorosilane 208, such as the tetrachlorosilaneshown, and water 206 are reacted with the OH groups 204, eithersimultaneously or in sequence, to produce the oxide layer 208 shown onsurface 203 of substrate 202 and byproduct HCl 210. In addition tochlorosilane precursors, chlorosiloxanes, fluorosilanes, andfluorosiloxanes may be used.

Subsequent to the reaction shown in FIG. 2, the surface of the oxidelayer 208 can be further reacted with water to replace Cl atoms on theupper surface of oxide layer 208 with H atoms, to create new OH groups(not shown). By controlling the amount of water used in both reactions,the frequency of OH reactive sites available on the oxide surface iscontrolled.

EXAMPLE TWO

In the preferred embodiment discussed below, a silicon oxide coating wasapplied over a glass substrate. The glass substrate was treated with anoxygen plasma in the presence of residual moisture which was present inthe process chamber (after pump down of the chamber to about 20 mTorr)to provide a clean surface (free from organic contaminants) and toprovide the initial OH groups on the glass surface.

Various process conditions for the subsequent reaction of the OH groupson the glass surface with vaporous tetrachlorosilane and water areprovided below in Table I, along with data related to the thickness androughness of the oxide coating obtained and the contact angle(indicating hydrophobicity/hydrophilicity) obtained under the respectiveprocess conditions. A lower contact angle indicates increasedhydrophilicity and an increase in the number of available OH groups onthe silicon oxide surface. TABLE I Deposition of a Silicon Oxide Layerof Varying Hydrophilicity Partial Partial Coating SiO₂ Order PressurePressure Reaction Coating Roughness Contact Run of SiCl₄ Vapor H₂O VaporTime Thickness (RMS, Angle*** No. Dosing (Torr) (Torr) (min.) (nm) nm)*(°) 1 First² 0.8  4.0 10  3 1 <5 SiCl₄ 2 First¹ 4.0 10.0 10 35 5 <5 H₂O3 First² 4.0 10.0 10 30 4 <5 SiCl₄ FOTS Partial Partial Coating SurfaceOrder Pressure Pressure Reaction Coating Roughness Contact of FOTS VaporH₂O Vapor Time Thickness (RMS, Angle*** Dosing (Torr) (Torr) (min.)(nm)** nm)* (°) 1 First³ 0.2 0.8 15  4 1 108 FOTS 2 First³ 0.2 0.8 15 365 109 FOTS 3 First³ 0.2 0.8 15 31 4 109 FOTS*Coating roughness is the RMS roughness measured by AFM (atomic forcemicroscopy).**The FOTS coating layer was a monolayer which added ≈1 nm in thickness.***Contact angles were measured with 18 MΩ D.I. water.¹The H₂O was added to the process chamber 10 seconds before the SiCl₄was added to the process chamber.²The SiCl₄ was added to the process chamber 10 seconds before the H₂Owas added to the process chamber.³The FOTS was added to the process chamber 5 seconds before the H₂O wasadded to the process chamber.4. The substrate temperature and the chamber wall temperature were each35° C. for both application of the SiO₂ bonding/bonding layer and forapplication of the FOTS organosilane overlying monolayer (SAM) layer.

We have discovered that very different film thicknesses and film surfaceroughness characteristics can be obtained as a function of the partialpressures of the precursors, despite the maintenance of the same timeperiod of exposure to the precursors. Table II below illustrates thisunexpected result. TABLE II Response Surface Design* Silicon Oxide LayerDeposition Partial Partial Substrate Coating Total Pressure Pressure andChamber Reaction Coating Surface Run Pressure SiCl₄ Vapor H₂O Vapor WallTemp. Time Thickness Roughness No. (Torr) (Torr) (Torr) (° C.) (min.)(nm) RMS (nm) 1 9.4 2.4 7 35 7 8.8 NA 2 4.8 0.8 4 35 7 2.4 1.29 3 6.42.4 4 35 4 3.8 1.39 4 14.0 4.0 10 35 7 21.9 NA 5 7.8 0.8 7 35 4 4.0 2.266 11.0 4.0 7 35 10 9.7 NA 7 11.0 4.0 7 35 4 10.5 NA 8 12.4 2.4 10 35 414.0 NA 9 6.4 2.4 4 35 10 4.4 1.39 10 9.4 2.4 7 35 7 8.7 NA 11 12.4 2.410 35 10 18.7 NA 12 9.4 2.4 7 35 7 9.5 NA 13 8.0 4.8 4 35 7 6.2 2.16 1410.8 0.8 10 35 7 6.9 NA 15 7.8 0.8 7 35 10 4.4 2.24*(Box-Behnken) 3 Factors, 3 Center PointsNA = Not Available, Not Measured

In addition to the tetrachlorosilane described above as a precursor foroxide formation, other chlorosilane precursors such a trichlorosilanes,dichlorosilanes work well as a precursor for oxide formation. Examplesof specific advantageous precursors include hexachlorodisilane (Si₂Cl₆)and hexachlorodisiloxane (Si₂Cl₆O). As previously mentioned, in additionto chlorosilanes, chlorosiloxanes, fluorosilanes, and fluorosiloxanesmay also be used as precursors.

Similarly, the vapor deposited silicon oxide coating from the SiCl₄ andH₂O precursors was applied over glass, polycarbonate, acrylic,polyethylene and other plastic materials using the same processconditions as those described above with reference to the siliconsubstrate. Prior to application of the silicon oxide coating, thesurface to be coated was treated with an oxygen plasma.

A silicon oxide coating of the kind described above can be applied overa self aligned monolayer (SAM) coating formed from an organic precursor,for example and not by way of limitation fromfluoro-tetrahydrooctyldimethylchlorosilane (FOTS). Prior to applicationof the silicon oxide coating, the surface of the SAM should be treatedwith an oxygen plasma. A FOTS coating surface requires a plasmatreatment of about 10-30 seconds to enable adhesion of the silicon oxidecoating. The plasma treatment creates reactive OH sites on the surfaceof the SAM layer, which sites can subsequently be reacted with SiCl₄ andwater precursors, as illustrated in FIG. 2, to create a silicon oxidecoating. This approach allows for deposition of multilayered molecularcoatings, where all of the layers may be the same, or some of the layersmay be different, to provide particular performance capabilities for themultilayered coating.

Functional properties designed to meet the end use application of thefinalized product can be tailored by either sequentially adding anorgano-silane precursor to the oxide coating precursors or by using anorgano-silane precursor(s) for formation of the last, top layer coating.Organo-silane precursor materials may include functional groups suchthat the silane precursor includes an alkyl group, an alkoxyl group, analkyl substituted group containing fluorine, an alkoxyl substitutedgroup containing fluorine, a vinyl group, an ethynyl group, or a glycolsubstituted group containing a silicon atom or an oxygen atom, by way ofexample and not by way of limitation. In particular, organic-containingprecursor materials such as (and not by way of limitation) silanes,chlorosilanes, fluorosilanes, methoxy silanes, alkyl silanes, aminosilanes, epoxy silanes, glycoxy silanes, and acrylosilanes are useful ingeneral.

Some of the particular precursors used to produce coatings are, by wayof example and not by way of limitation, perfluorodecyltrichlorosilanes(FDTS), undecenyltrichlorosilanes (UTS), vinyl-trichlorosilanes (VTS),decyltrichlorosilanes (DTS), octadecyltrichlorosilanes (OTS),dimethyldichlorosilanes (DDMS), dodecenyltricholrosilanes (DDTS),fluoro-tetrahydrooctyldimethylchlorosilanes (FOTS),perfluorooctyldimethylchlorosilanes, aminopropylmethoxysilanes (APTMS),fluoropropylmethyldichlorosilanes, andperfluorodecyldimethylchlorosilanes. The OTS, DTS, UTS, VTS, DDTS, FOTS,and FDTS are all trichlorosilane precursors. The other end of theprecursor chain is a saturated hydrocarbon with respect to OTS, DTS, andUTS; contains a vinyl functional group, with respect to VTS and DDTS;and contains fluorine atoms with respect to FDTS (which also hasfluorine atoms along the majority of the chain length). Other usefulprecursors include 3-aminopropyltrimethoxysilane (APTMS), which providesamino functionality, and 3-glycidoxypropyltrimethoxysilane (GPTMS). Oneskilled in the art of organic chemistry can see that the vapor depositedcoatings from these precursors can be tailored to provide particularfunctional characteristics for a coated surface.

Most of the silane-based precursors, such as commonly used di- andtri-chlorosilanes, for example and not by way of limitation, tend tocreate agglomerates on the surface of the substrate during the coatingformation. These agglomerates can cause structure malfunctioning orstiction. Such agglomerations are produced by partial hydrolysis andpolycondensation of the polychlorosilanes. This agglomeration can beprevented by precise metering of moisture in the process ambient whichis a source of the hydrolysis, and by carefully controlled metering ofthe availability of the chlorosilane precursors to the coating formationprocess. The carefully metered amounts of material and carefultemperature control of the substrate and the process chamber walls canprovide the partial vapor pressure and condensation surfaces necessaryto control formation of the coating on the surface of the substraterather than promoting undesired reactions in the vapor phase or on theprocess chamber walls.

EXAMPLE THREE

When the oxide-forming silane and the organo-silane which includes thefunctional moiety are deposited simultaneously (co-deposited), thereaction may be so rapid that the sequence of precursor addition to theprocess chamber becomes critical. For example, in a co-depositionprocess of SiCl₄/FOTS/H₂O, if the FOTS is introduced first, it depositson the glass substrate surface very rapidly in the form of islands,preventing the deposition of a homogeneous composite film. Examples ofthis are provided in Table III, below.

When the oxide-forming silane is applied to the substrate surface first,to form the oxide layer with a controlled density of potential OHreactive sites available on the surface, the subsequent reaction of theoxide surface with a FOTS precursor provides a uniform film without thepresence of agglomerated islands of polymeric material, examples of thisare provided in Table III below. TABLE III Deposition of a Coating Upona Silicon Substrate* Using Silicon tetrachloride and FOTS PrecursorsPartial Partial Partial Substrate Total Pressure Pressure Pressure andChamber Pressure SiCl₄ Vapor FOTS Vapor H₂O Vapor Wall Temp. Run No.(Torr) (Torr) (Torr) (Torr) (° C.) 1 FOTS + H₂O 1 — 0.20 0.80 35 2 H₂O +SiCl₄ 14 4 — 10 35 followed by FOTS + H₂O 1 — 0.20 0.80 35 3 FOTS +SiCl₄ + 14.2 4 0.20 10 35 H₂O 4 SiCl₄ + H₂O 14 4 — 10 35 5 SiCl₄ + H₂O5.8 0.8 — 5 35 6 SiCl₄ + H₂O 14 4 — 10 35 repeated twice CoatingReaction Coating Roughness Contact Time Thickness (nm)** Angle*** (min.)(nm) RMS (°) 1 15 0.7 0.1 110 2 10 + 15 35.5 4.8 110 3 15 1.5 0.8 110 410 30 0.9 <5 5 10 4 0.8 <5 6 10 + 10 55 1.0 <5*The silicon substrates used to prepare experimental samples describedherein exhibited an initial surface RMS roughness in the range of about0.1 nm, as measured by Atomic Force Microscope (AFM).**Coating roughness is the RMS roughness measured by AFM.***Contact angles were measured with 18 MΩ D.I. water.

An example process description for Run No. 2 was as follows.

Step 1. Pump down the reactor and purge out the residual air andmoisture to a final baseline pressure of about 30 mTorr or less.

Step 2. Perform O₂ plasma clean of the substrate surface to eliminateresidual surface contamination and to oxygenate/hydroxylate thesubstrate. The cleaning plasma is an oxygen-containing plasma. Typicallythe plasma source is a remote plasma source, which may employ aninductive power source. However, other plasma generation apparatus maybe used. In any case, the plasma treatment of the substrate is typicallycarried out in the coating application process chamber. The plasmadensity/efficiency should be adequate to provide a substrate surfaceafter plasma treatment which exhibits a contact angle of about 10° orless when measured with 18 MΩ D.I. water. The coating chamber pressureduring plasma treatment of the substrate surface in the coating chamberwas 0.5 Torr, and the duration of substrate exposure to the plasma was 5minutes.

Step 3. Inject SiCl₄ and within 10 seconds inject water vapor at aspecific partial pressure ratio to the SiCl₄, to form a silicon oxidebase layer on the substrate. For example, for the glass substratediscussed in Table III, 1 volume (300 cc at 100 Torr) of SiCl₄ to apartial pressure of 4 Torr was injected, then, within 10 seconds 10volumes (300 cc at 17 Torr each) of water vapor were injected to producea partial pressure of 10 Torr in the process chamber, so that thevolumetric pressure ratio of water vapor to silicon tetrachloride isabout 2.5. The substrate was exposed to this gas mixture for 1 min to 15minutes, typically for about 10 minutes. The substrate temperature inthe examples described above was in the range of about 35° C. Substratetemperature may be in the range from about 20° C. to about 80° C. Theprocess chamber surfaces were also in the range of about 35° C.

Step 4. Evacuate the reactor to <30 mTorr to remove the reactants.

Step 5. Introduce the chlorosilane precursor and water vapor to form ahydrophobic coating. In the example in Table III, FOTS vapor wasinjected first to the charging reservoir, and then into the coatingprocess chamber, to provide a FOTS partial pressure of 200 mTorr in theprocess chamber, then, within 10 seconds, H₂O vapor (300 cc at 12 Torr)was injected to provide a partial pressure of about 800 mTorr, so thatthe total reaction pressure in the chamber was 1 Torr. The substrate wasexposed to this mixture for 5 to 30 minutes, typically 15 minutes, wherethe substrate temperature was about 35° C. Again, the process chambersurface was also at about 35° C.

An example process description for Run No. 3 was as follows.

Step 1. Pump down the reactor and purge out the residual air andmoisture to a final baseline pressure of about 30 mTorr or less.

Step 2. Perform remote O₂ plasma clean to eliminate residual surfacecontamination and to oxygenate/hydroxylate the glass substrate. Processconditions for the plasma treatment were the same as described abovewith reference to Run No. 2.

Step 3. Inject FOTS into the coating process chamber to produce a 200mTorr partial pressure in the process chamber. Then, inject 1 volume(300 cc at 100 Torr) of SiCl₄ from a vapor reservoir into the coatingprocess chamber, to a partial pressure of 4 Torr in the process chamber.Then, within 10 seconds inject 10 volumes (300 cc at 17 Torr each) ofwater vapor from a vapor reservoir into the coating process chamber, toa partial pressure of 10 Torr in the coating process chamber. Totalpressure in the process chamber is then about 14 Torr. The substratetemperature was in the range of about 35° C. for the specific examplesdescribed, but could range from about 15° C. to about 80° C. Thesubstrate was exposed to this three gas mixture for about 1-15 minutes,typically about 10 minutes.

Step 4. Evacuate the process chamber to a pressure of about 30 mTorr toremove excess reactants.

EXAMPLE FOUR

FIGS. 3A and 3B are schematics of AFM (atomic force microscope) imagesof surfaces of silicon oxide bonding coatings as applied over a siliconsubstrate. The initial silicon substrate surface RMS roughness wasdetermined to be less than about 0.1 nm. FIG. 3A illustrates adeposition process in which the substrate was silicon. The surface ofthe silicon was exposed to an oxygen plasma in the manner previouslydescribed herein for purposes of cleaning the surface and creatinghydroxyl availability on the silicon surface. SiCl₄ was charged to theprocess chamber from a SiCl₄ vapor reservoir, creating a partialpressure of 0.8 Torr in the coating process chamber. Within 10 seconds,H₂O vapor was charged to the process chamber from a H₂O vapor reservoir,creating a partial pressure of 4 Torr in the coating process chamber.The total pressure in the coating process chamber was 4.8 Torr. Thesubstrate temperature and the temperature of the process chamber wallswas about 35° C. The substrate was exposed to the mixture of SiCl₄ andH₂O for a time period of 10 minutes. The silicon oxide coating thicknessobtained was about 3 nm. The coating roughness in RMS was 1.4 nm and Rawas 0.94 nm.

FIG. 3B illustrates a deposition process in which the substrate wassilicon. The surface of the silicon was exposed to an oxygen plasma inthe manner previously described herein for purposes of cleaning thesurface and creating hydroxyl availability on the silicon surface. SiCl₄was charged to the process chamber from a SiCl₄ vapor reservoir,creating a partial pressure of 4 Torr in the coating process chamber.Within 10 seconds, H₂O vapor was charged to the process chamber from aH₂O vapor reservoir, creating a partial pressure of 10 Torr in thecoating process chamber. The total pressure in the coating processchamber was 14 Torr. The substrate temperature and the temperature ofthe process chamber walls was about 35° C. The substrate was exposed tothe mixture of SiCl₄ and H₂O for a time period of 10 minutes. Thesilicon oxide coating thickness obtained was about 30 nm. The coatingroughness in RMS was 4.2 nm and Ra was 3.4 nm.

EXAMPLE FIVE

FIG. 4 shows a graph 400 of the dependence of the water contact angle(an indication of hydrophobicity of a surface) as a function of thesubstrate exposure time (reaction time) with an organo-silane coatinggenerated from a DDMS (dimethyldichlorosilane) precursor. The siliconsubstrate was cleaned and functionalized to provide surface hydroxylgroups by an oxygen plasma treatment of the kind previously describedherein. DDMS was then applied at a partial pressure of 1 Torr, followedwithin 10 seconds by H₂O applied at a partial pressure of 2 Torr, toproduce a total pressure within the process chamber of 3 Torr.

In FIG. 4, graph 400, the substrate exposure period with respect to theDDMS and H₂O precursor combination is shown in minutes on axis 402, withthe contact angle shown in degrees on axis 404. Curve 406 illustratesthat it is possible to obtain a wide range of hydrophobic surfaces bycontrolling the process variables in the manner of the presentinvention. The typical standard deviation of the contact angle was lessthan 2 degrees across the substrate surface. Both wafer-to wafer andday-to day repeatability of the water contact angle were within themeasurement error of ∓2° for a series of silicon samples.

FIG. 5 illustrates contact angles for a series of surfaces exposed towater, where the surfaces exhibited different hydrophobicity, with anincrease in contact angle representing increased hydrophobicity. Thisdata is provided as an illustration to make the contact angle datapresented in tables herein more meaningful.

EXAMPLE SIX

FIG. 6A shows a three dimensional schematic 600 of film thickness of asilicon oxide bonding layer coating deposited on a silicon surface as afunction of the partial pressure of silicon tetrachloride and thepartial pressure of water vapor present in the process chamber duringdeposition of the silicon oxide coating, where the temperature of thesubstrate and of the coating process chamber walls was about 35° C., andthe time period the silicon substrate was exposed to the coatingprecursors was four minutes after completion of addition of allprecursor materials. The precursor SiCl₄ vapor was added to the processchamber first, with the precursor H₂O vapor added within 10 secondsthereafter. The partial pressure of the H₂O in the coating processchamber is shown on axis 602, with the partial pressure of the SiCl₄shown on axis 604. The film thickness is shown on axis 606 in Angstroms.The film deposition time after addition of the precursors was 4 minutes.The thinner coatings exhibited a smoother surface, with the RMSroughness of a coating at point 608 on Graph 600 being in the range of 1nm (10 Å). The thicker coatings exhibited a rougher surface, which wasstill smooth relative to coatings generally known in the art. At point610 on Graph 600, the RMS roughness of the coating was in the range of 4nm (40 Å).

FIG. 7A shows a three dimensional schematic 700 of the film roughness inRMS, nm which corresponds with the coated substrate for which thecoating thickness is illustrated in FIG. 6A. The partial pressure of theH₂O in the coating process chamber is shown on axis 702, with thepartial pressure of the SiCl₄ shown on axis 704. The film roughness inRMS, nm is shown on axis 706. The film deposition time after addition ofall of the precursors was 7 minutes. As previously mentioned, thethinner coatings exhibited a smoother surface, with the RMS roughness ofa coating at point 708 being in the range of 1 nm (10 Å) and theroughness at point 710 being in the range of 4 nm (40 Å).

FIG. 6B shows a three dimensional schematic 620 of film thickness of thesilicon oxide bonding layer illustrated in FIG. 6A as a function of thewater vapor partial pressure and the time period the substrate wasexposed to the coating precursors after completion of addition of allprecursor materials. The time period of exposure of the substrate isshown on axis 622 in minutes, with the H₂O partial pressure shown onaxis 624 in Torr, and the oxide coating thickness shown on axis 626 inAngstroms. The partial pressure of SiCl₄ in the silicon oxide coatingdeposition chamber was 0.8 Torr.

FIG. 6C shows a three dimensional schematic 640 of film thickness of thesilicon oxide bonding layer illustrated in FIG. 6A as a function of thesilicon tetrachloride partial pressure and the time period the substratewas exposed to the coating precursors after completion of addition ofall precursor materials. The time period of exposure is shown on axis642 in minutes, with the SiCl₄ partial pressure shown on axis 646 inTorr, and the oxide thickness shown on axis 646 in Angstroms. The H₂Opartial pressure in the silicon oxide coating deposition chamber was 4Torr.

A comparison of FIGS. 6A-6C makes it clear that it is the partialpressure of the H₂O which must be more carefully controlled in order toensure that the desired coating thickness is obtained.

FIG. 7B shows a three dimensional schematic 720 of film roughness of thesilicon oxide bonding layer illustrated in FIG. 6B as a function of thewater vapor partial pressure and the time period the substrate wasexposed to the coating precursors after completion of addition of allprecursor materials. The time period of exposure of the substrate isshown on axis 722 in minutes, with the H₂O partial pressure shown onaxis 724 in Torr, and the surface roughness of the silicon oxide layershown on axis 726 in RMS, nm. The partial pressure of the SiCl₄ in thesilicon oxide coating deposition chamber was 2.4 Torr.

FIG. 7C shows a three dimensional schematic 740 of film roughnessthickness of the silicon oxide bonding layer illustrated in FIG. 6C as afunction of the silicon tetrachloride partial pressure and the timeperiod the substrate was exposed to the coating precursors aftercompletion of addition of all precursor materials. The time period ofexposure is shown on axis 642 in minutes, with the SiCl₄ partialpressure shown on axis 646 in Torr, and the surface roughness of thesilicon oxide layer shown on axis 746 in RMS, nm. The partial pressureof the H₂O in the silicon oxide coating deposition chamber was 7.0 Torr.

A comparison of FIGS. 7A-7C makes it clear that it is the partialpressure of the H₂O which must be more carefully controlled in order toensure that the desired roughness of the coating surface is obtained.

FIG. 8A is a graph 800 which shows the hydrophilicity of an oxide-basedlayer on different substrate materials, as a function of the thicknessof the oxide-based layer. The data presented in FIG. 8A indicates thatto obtain full surface coverage by the oxide-based layer, it isnecessary to apply a different thickness of oxide-based layer dependingon the underlying substrate material.

In particular, the oxide-based layer was a silicon-oxide-based layerprepared in general in the manner described above, with respect to RunNo. 4 in Table III, but where the nominal amounts of reactants chargedand/or reaction time of the reactants were varied to provide the desiredsilicon oxide layer thickness, which is specified on axis 802 of FIG.8A. The graph 800 shows the contact angle for a deionized (DI) waterdroplet, in degrees, on axis 804, as measured for a given oxide-basedlayer surface, as a function of the thickness of the oxide-based layerin Angstroms shown on axis 802. Curve 806 illustrates asilicon-oxide-based layer deposited over a single crystal silicon wafersurface. Curve 808 represents a silicon-oxide-based layer deposited overa soda lime glass surface. Curve 810 illustrates a silicon-oxide-basedlayer deposited over a stainless steel surface. Curve 812 shows asilicon-oxide-based layer deposited over a polystyrene surface. Curve814 illustrates a silicon-oxide-based layer deposited over an acrylicsurface.

Graph 800 shows that a single crystal silicon substrate required onlyabout a 30 Å thick coating of a silicon oxide-based layer to provide aDI water droplet contact angle of about 5 degrees, indicating themaximum hydrophilicity typically obtained using a silicon oxide-basedlayer. The glass substrate required about 80 Å of the siliconoxide-based layer to provide a contact angle of about 5 degrees. Thestainless steel substrate required a silicon oxide-based layer thicknessof about 80 Å to provide the contact angle of 5 degrees. The polystyrenesubstrate required a silicon oxide-based layer thickness of about 80 Åto provide the contact angle of 5 degrees. And, the acrylic substraterequired a silicon oxide-based layer thickness of about 150 Å. It shouldbe mentioned that the hydrophilicity indicated in FIG. 8A was measuredimmediately after completion of the coating process, since the nominalvalue measured may change during storage.

FIG. 8B shows a graph 820, which illustrates the relationship betweenthe hydrophobicity obtained on the surface of a SAM layer deposited fromperfluorodecyltrichlorosilane (FDTS), as a function of the thickness ofan oxide-based layer over which the FDTS layer was deposited. The oxidelayer was deposited in the manner described above, usingtetrachlorosilane precursor, with sufficient moisture that a siliconoxide surface having sufficient hydroxyl groups present to provide asurface contact angle (with a DI water droplet) of 5 degrees wasproduced.

The oxide-based layer and the organic-based layer generated from an FDTSprecursor were deposited as follows: The process chamber was vented andthe substrate was loaded into the chamber. Prior to deposition of theoxide-based layer, the surface of the substrate was plasma cleaned toeliminate residual surface contamination and to oxygenate/hydroxylatethe substrate. The chamber was pumped down to a pressure in the range ofabout 30 mTorr or less. The substrate surface was then plasma treatedusing a low density, non-physically-bombarding plasma which was createdexternally from a plasma source gas containing oxygen. The plasma wascreated in an external chamber which is a high efficiency inductivelycoupled plasma generator, and was fed into the substrate processingchamber. The plasma treatment was in the manner previously describedherein, where the processing chamber pressure during plasma treatmentwas in the range of about 0.5 Torr, the temperature in the processingchamber was about 35° C., and the duration of substrate exposure to theplasma was about 5 minutes.

After plasma treatment, the processing chamber was pumped down to apressure in the range of about 30 mTorr or less to evacuate remainingoxygen species. Optionally, processing chamber may be purged withnitrogen up to a pressure of about 10 Torr to about 20 Torr and thenpumped down to the pressure in the range of about 30 mTorr. An adheringoxide-based layer was then deposited on the substrate surface. Thethickness of the oxide-based layer depended on the substrate material,as previously discussed. SiCl₄ vapor was injected into the processchamber at a partial pressure to provide a desired nominal oxide-basedlayer thickness. To produce an oxide-based layer thickness ranging fromabout 30 Å to about 400 Å, typically the partial pressure in the processchamber of the SiCl₄ vapor ranges from about 0.5 Torr to about 4 Torr,more typically from about 1 Torr to about 3 Torr. Typically, withinabout 10 seconds of injection of the SiCl₄ vapor, water vapor wasinjected at a specific partial pressure ratio to the SiCl₄ to form theadhering silicon-oxide based layer on the substrate. Typically thepartial pressure of the water vapor ranges from about 2 Torr to about 8Torr, and more typically from about 4 Torr to about 6 Torr. (Severalvolumes of SiCl₄ and/or several volumes of water may be injected intothe process chamber to achieve the total partial pressures desired, aspreviously described herein.) The reaction time to produce the oxidelayer may range from about 5 minutes to about 15 minutes, depending onthe processing temperature, and in the exemplary embodiments describedherein the reaction time used was about 10 minutes at about 35° C.

After deposition of the oxide-based layer, the chamber was once againpumped down to a pressure in the range of about 30 mTorr or less.Optionally, the processing chamber may be purged with nitrogen up to apressure of about 10 Torr to about 20 Torr and then pumped down to thepressure in the range of about 30 mTorr, as previously described. Theorganic-based layer deposited from an FDTS precursor was then producedby injecting FDTS into the process chamber to provide a partial pressureranging from about 30 mTorr to about 1500 mTorr, more typically rangingfrom about 100 mTorr to about 300 mTorr. The exemplary embodimentsdescribed herein were typically carried out using an FDTS partialpressure of about 150 mTorr. Within about 10 seconds after injection ofthe FDTS precursor, water vapor was injected into the process chamber toprovide a partial pressure of water vapor ranging from about 300 mTorrto about 1000 mTorr, more typically ranging from about 400 mTorr toabout 800 mTorr. The exemplary embodiments described herein weretypically carried out using a water vapor partial pressure of about 600mTorr. The reaction time for formation of the organic-based layer (aSAM) ranged from about 5 minutes to about 30 minutes, depending on theprocessing temperature, more typically from about 10 minutes to about 20minutes, and in the exemplary embodiments described herein the reactiontime used was about 15 minutes at about 35° C.

The data presented in FIG. 8B indicates that to obtain the maximumhydrophobicity at the surface of the FDTS-layer, it is not onlynecessary to have an oxide-based layer thickness which is adequate tocover the substrate surface, but it is also necessary to have a thickerlayer in some instances, depending on the substrate underlying theoxide-based layer Since the silicon oxide layer is conformal, it wouldappear that the increased thickness is not necessary to compensate forroughness, but has a basis in the chemical composition of the substrate.However, as a matter of interest, the initial roughness of the siliconwafer surface was about 0.1 RMS nm, and the initial roughness of theglass surface was about 1-2 RMS nm.

In particular, the oxide-based layer was a silicon-oxide-based layerprepared in the manner described above, with respect to FIG. 8A. Thegraph 820 shows the contact angle of a DI water droplet, in degrees, onaxis 824, as measured for an oxide-based layer surface over differentsubstrates, as a function of the thickness of the oxide-based layer inAngstroms shown on axis 822. Curve 826 illustrates a silicon-oxide-basedlayer deposited over a single crystal silicon wafer surface describedwith reference to FIG. 8A. Curve 828 represents a silicon-oxide-basedlayer deposited over a glass surface as described with reference to FIG.8A. Curve 830 illustrates a silicon-oxide-based layer deposited over astainless steel surface, as described with reference to FIG. 8A. Curve832 shows a silicon-oxide-based layer deposited over a polystyrenesurface, as described with reference to FIG. 8A. Curve 834 illustrates asilicon-oxide-based layer deposited over an acrylic surface describedwith reference to FIG. 8A. The FDTS-generated SAM layer provides anupper surface containing fluorine atoms, which is generally hydrophobicin nature. The maximum contact angle provided by thisfluorine-containing upper surface is about 117 degrees. As illustratedin FIG. 8B, this maximum contact angle, indicating an FDTS layercovering the entire substrate surface is only obtained when theunderlying oxide-based layer also covers the entire substrate surface ata particular minimum thickness. There appears to be another factor whichrequires a further increase in the oxide-based layer thickness, over andabove the thickness required to fully cover the substrate, with respectto some substrates. It appears this additional increase in oxide-layerthickness is necessary to fully isolate the surface organic-based layer,a self-aligned-monolayer (SAM), from the effects of the underlyingsubstrate. It is important to keep in mind that the thickness of the SAMdeposited from the FDTS layer is only about 10 Å to about 20 Å.

Graph 820 shows that a SAM surface layer deposited from FDTS over asingle crystal silicon substrate exhibits the maximum contact angle ofabout 117 degrees when the oxide-based layer overlying the singlecrystal silicon has a thickness of about 30 Å or greater. The surfacelayer deposited from FDTS over a glass substrate exhibits the maximumcontact angle of about 117 degrees when the oxide-based layer overlyingthe glass substrate has a thickness of about 150 Å or greater. Thesurface layer deposited from FDTS over the stainless steel substrateexhibits the maximum contact angle of about 117 degrees when theoxide-based layer overlying the stainless steel substrate has athickness of between 80 Å and 150 Å or greater. The surface layerdeposited from FDTS over the polystyrene substrate exhibits the maximumcontact angle when the oxide-based layer overlying the polystyrenesubstrate has a thickness of 150 Å or greater. The surface layerdeposited from FDTS over the acrylic substrate exhibits the maximumcontact angle when the oxide-based layer overlying the acrylic substratehas a thickness of 400 Å or greater.

FIGS. 9A through 9C illustrate the stability of the hydrophobic surfaceprovided by the SAM surface layer deposited from FDTS, when the coatedsubstrate is immersed in deionized (DI) water for a specified timeperiod. Each test specimen was plasma treated, then coated with oxideand SAM deposited from an FDTS precursor. Each test specimen size wasabout 1 cm² on the two major surfaces, and was coated on all sides. Eachspecimen was immersed into distilled water present in a 6 inch diameterround glass dish, without any means for circulating the water around thesample, and was allowed to stand in the water at atmospheric pressureand at room temperature (about 27° C). After the time period specified,each specimen was blown dry using a gentle nitrogen gas sparging; therewas no baking of the test specimens. After drying, a DI contact anglewas measured on the test specimen surface using the contact angle testmethod previously described herein, which is generally known in the art.

FIGS. 9A -9C indicate that, depending on the underlying substrate, thereare some instances where a thicker layer of oxide-based materialdeposited over the substrate is not able to provide a stable structureof the kind which ensures that the upper surface of the organic-basedlayer will maintain the desired surface properties in terms ofhydrophobicity.

FIG. 9A shows a graph 900 illustrating surface physical property data(contact angle with a DI water droplet) for an approximately 15 Å thicklayer of a SAM deposited from FDTS, where the underlying substrate is asingle crystal silicon substrate (Curve 906); or, a single crystalsilicon substrate having a 150 Å thick layer of silicon oxide depositedover the silicon substrate (Curve 908); or, a single crystal siliconsubstrate having a 400 Å thick layer of silicon oxide deposited over thesilicon substrate (Curve 910). The DI water droplet contact angle isshown on axis 904 in degrees; the number of days of immersion of thesubstrate (with overlying oxide and SAM layer in place) is shown on axis902 in days. The silicon oxide layer and the overlying layer of SAMdeposited from FDTS were deposited in the manner described above withrespect to FIGS. 8A-8B. For a silicon substrate (which provides ahydrophilic surface) the stability of the organic-based layer in termsof the hygroscopic surface provided is relatively good for each of thesamples, and somewhat better for the test specimens where there is anoxide-based layer underlying the organic-based layer. The test specimenshaving the oxide-based layer over the silicon substrate maintained acontact angle of about 103-105 after 5 days of water immersion, whilethe test specimen without the oxide-based layer dropped to a contactangle of about 98.

FIG. 9B shows a graph 960 illustrating stability in DI water for thesame organic-based layer applied over the same oxide-based layers in thesame manner as described with respect to FIG. 9A, where the initialsubstrate surface was polystyrene. The DI water droplet contact angle isshown on axis 964 in degrees; the number of days of immersion of thesubstrate (with overlying oxide and SAM layer in place) is shown on axis962 in days. [01581 The test specimen which did not have an oxide-basedlayer deposited over the substrate (Curve 966) exhibited a low contactangle in the range of about 200, indicating that plasma treatment causedthe polystyrene surface to become hydrophilic. The test specimens whichdid have an oxide-based layer deposited over the substrate (a 150 Åthick layer of silicon oxide deposited over the polystyrene substrate(Curve 968) or a 400 Å thick layer of silicon oxide (Curve 970))initially exhibited the hydrophobic surface properties expected when aSAM film is deposited over the substrate. The contact angle was about117, indicating approximately the maximum amount of hydrophobicity whichis obtainable from the surface of a SAM deposited from FDTS. Thiscontact angle decreased drastically, in less than one day, to a contactangle in the range of about 4-8 degrees. This catastrophic failure isindicative of a lack of adhesion of the oxide layer to the polystyrenematerial surface.

FIG. 9C shows a graph 980 of the stability in DI water for the sameorganic-based layer applied over the same two thicknesses of anoxide-based layer as those shown in FIG. 9A, where the initial substratesurface is acrylic. The contact angle in DI water is shown on axis 989,while the number of days if test specimen immersion in DI water is shownon axis 982.

Curve 986 shows the contact angle for a test specimen where theapproximately 15 Å thick layer of a SAM deposited from FDTS was applieddirectly over the acrylic substrate. Curve 988 shows the contact anglefor a test specimen where a 150 Å thick silicon oxide layer was appliedover the acrylic substrate surface prior to application of the SAMlayer. Curve 990 shows the contact angle for a test specimen where a 400Å thick silicon oxide layer was applied over the acrylic substratesurface prior to application of the SAM layer. While increasing thethickness of the oxide layer helped to increase the initial hydrophobicproperties of the substrate surface (indicating improved bonding of theSAM layer or improved surface coverage by the SAM layer), the structurewas not stable, as indicated by the change in contact angle over time.In an effort to provide a more stable structure, we applied amultilayered structure over the acrylic substrate, with the multilayeredstructure including a series of five pairs of oxide-basedlayer/organic-based layer, to provide an organic-based surface layer.Curve 922 shows the stability of the hydrophobic surface layer obtainedwhen this multilayered structure was applied. This indicates that it ispossible to provide a stable structure which can withstand extendedperiods of water immersion by creating the multilayered structuredescribed. The number of pairs (sets) of oxide-based layer/organic-basedlayer which are required depends on the substrate material. When thesubstrate material is acrylic, the number of sets of oxide-basedlayer/organic-based layer which should be used is 5 sets. For othersubstrate materials, the number of sets of oxide-basedlayer/organic-based layer may be fewer; however, use of at least twosets of layers helps provide a more mechanically stable structure.

The stability of the deposited SAM organic-based layers can be increasedby baking for about one half hour at 110° C., to crosslink theorganic-based layers. Baking of a single pair of layers is not adequateto provide the stability which is observed for the multilayeredstructure, but baking can even further improve the performance of themultilayered structure.

The integrated method for creating a multilayered structure of the kinddescribed above includes: Treatment of the substrate surface to removecontaminants and to provide either —OH or halogen moieties on thesubstrate surface, typically the contaminants are removed using a lowdensity oxygen plasma, or ozone, or ultra violet (UV) treatment of thesubstrate surface. The —OH or halogen moieties are commonly provided bydeposition of an oxide-based layer in the manner previously describedherein. A first SAM layer is then vapor deposited over the oxide-basedlayer surface. The surface of the first SAM layer is then treated usinga low density isotropic oxygen plasma, where the treatment is limited tojust the upper surface of the SAM layer, with a goal of activating thesurface of the first SAM layer. It is important not to etch away the SAMlayer down to the underlying oxide-based layer. By adjusting the oxygenplasma conditions and the time period of treatment, one skilled in theart will be able to activate the first SAM layer surface while leavingthe bottom portion of the first SAM layer intact. Typically, the surfacetreatment is similar to a substrate pretreatment, where the surface istreated with the low density isotropic oxygen plasma for a time periodranging from about 25 seconds to about 60 seconds, and typically forabout 30 seconds. In the apparatus described herein the pretreatment iscarried out by pumping the process chamber to a pressure ranging fromabout 15 mTorr to about 20 mTorr, followed by flowing anexternally-generated oxygen-based plasma into the chamber at a plasmaprecursor oxygen flow rate of about 50 sccm to 200 sccm, typically atabout 150 sccm in the apparatus described herein, to create about 0.4Torr in the substrate processing chamber.

After activation of the surface of the first SAM layer using theoxygen-based plasma, a second oxide-based layer is vapor deposited-overthe first sam layer. A second SAM layer is then vapor deposited over thesecond oxide-based layer. The second SAM layer is then plasma treated toactivate the surface of the second SAM layer. The process of depositionof oxide-based layer followed by deposition of SAM layer, followed byactivation of the SAM surface may be repeated a nominal number of timesto produce a multilayered structure which provides the desiredmechanical strength and surface properties. Of course there typically isno activation step after deposition of the final surface layer of themultilayered structure, where the surface properties desired are thoseof the final organic-based layer. It is important to mention that thefinal organic-based layer may be different from other organic-basedlayers in the structure, so that the desired mechanical properties forthe structure may be obtained, while the surface properties of the finalorganic-based layer are achieved. The final surface layer is typically aSAM layer, but may also be an oxide-based layer.

As described previously herein, the thickness and roughness of theinitial oxide-based layer can be varied over wide ranges by choosing thepartial pressure of precursors, the temperature during vapor deposition,and the duration time of the deposition. Subsequent oxide-based layerthicknesses may also be varied, where the roughness of the surface maybe adjusted to meet end use requirements. The thickness of anorganic-based layer which is applied over the oxide-based layer willdepend on the precursor molecular length of the organic-based layer. Inthe instance where the organic-based layer is a SAM, such as FOTS, forexample, the thickness of an individual SAM layer will be in the rangeof about 15 Å. The thicknesses for a variety of SAM layers are known inthe art. Other organic-based layer thicknesses will depend on thepolymeric structure which is deposited using polymer vapor depositiontechniques. The organic-based layers deposited may be different fromeach other, and may present hydrophilic or hydrophobic surfaceproperties of varying degrees. In some instances, the organic-basedlayers may be formed from a mixture of more than one precursor. In someinstances, the organic-based layer may be vapor deposited simultaneouslywith an oxide-based structure to provide crosslinking of organic andinorganic materials and the formation of a dense, essentiallypinhole-free structure.

EXAMPLE SEVEN

One example of an application for the multilayered coating whichcomprise a plurality of oxide-based layers and a plurality oforganic-based layers is an ink jet of the kind commonly used inprinting. The ability to print a fine character size depends on the sizeof the opening through which the ink flows prior to reaching the surfaceto be printed. In addition, depending on the ink to be used, in order toobtain ease of flow of the ink over the surface of the opening and thedesired jetting action, the surface may need to be hydrophilic orhydrophobic in nature, with various degrees of contact angle between theink and the surface of the opening being used to provide an advantage.

FIG. 10A shows a nozzle structure 1000 where the nozzle includes twochambers, a first chamber 1010 having a first diameter, d-1, and asecond chamber 1012 having a second, smaller diameter, d-2. The nozzlestructure 1000 has a surface 1005 which is typically micromachined froma substrate such as silicon. A multilayered coating of the kinddescribed herein is applied over the surface 1005, as a means ofdecreasing d-1 and d-2, so that finer patterns can be printed, whileproviding an exterior surface 1003 having the desired surfaceproperties, depending on the liquid 1004 which is to be flowed oversurface 1003.

FIG. 10B shows an orifice structure 1020 which employs the same conceptof the multilayered coating as that used with reference to FIG. 10A. Theorifice structure 1020 has a surface 1025 which is typicallymicromachined from a substrate such as silicon. A multilayered coatingof the kind described herein is applied over the surface 1025 to providea surface 1023 having the desired surface properties, depending on theliquid 1024 which is to be flowed over surface 1023.

FIGS. 11A through 11C provide comparative examples which furtherillustrate the improvement in structure stability and surface propertiesfor a SAM which is deposited from a FOTS precursor over a multilayeredstructure of the kind described above (with respect to a SAM depositedfrom FDTS).

FIG. 11A shows a graph 1100 which illustrates the improvement in DIwater stability of a SAM when the organic-based precursor wasfluoro-tetrahydrooctyldimethylchlorosilanes (FOTS) and the multilayeredstructure described was present beneath the FOTS based SAM layer. Curve1108 shows physical property data (contact angle with a DI waterdroplet) for an approximately 800 Å thick layer of a SAM deposited fromFOTS directly upon a single crystal silicon substrate which was oxygenplasma pre-treated in the manner previously described herein. The DIwater droplet contact angle is shown on axis 1104 in degrees; the numberof days of immersion of the substrate (with overlying oxide and SAMlayer in place) is shown on axis 1102 in days. For a silicon substrate(which provides a hydrophilic surface), with the FOTS applied directlyover the substrate, the stability of the organic-based SAM layer, interms of the hygroscopic surface provided, decreases gradually from aninitial contact angle of about 108° to a contact angle of less thanabout 90° after a 14 day time period, as illustrated by curve 1106.

This decrease in contact angle compares with a decrease in contact anglefrom about 110° to about 105° over the 14 day time period, when thestructure is a series of five pairs of silicon oxide/FOTS SAM layers,with a SAM surface layer, as illustrated by curve 1108.

FIG. 11B shows a graph 1130 illustrating stability in DI water for thesame FOTS organic-based SAM layer applied directly over the substrate orapplied over a series of five pairs of silicon oxide/FOTS SAM layers,when the substrate is soda lime glass. The DI water droplet contactangle is shown on axis 1124 in degrees; the number of days of immersionof the substrate (with overlying oxide and SAM layer in place) is shownon axis 1122 in days.

When the FOTS SAM layer was applied directly over the substrate, thestability of the organic-based SAM layer, in terms of the hygroscopicsurface provided, decreased gradually from an initial contact angle ofabout 98° to a contact angle of less than about 88° after a 14 day timeperiod, as illustrated by curve 1126. This compares with a decrease incontact angle from about 108° to about 107° over the 14 day time period,when the structure is a series of five pairs of silicon oxide/FOTS SAMlayers, as illustrated by curve 1128.

FIG. 11C shows a graph 1130 of the temperature stability in air at 250°C. for the same FOTS organic-based SAM layer applied directly over asingle crystal silicon substrate versus the five pairs of siliconoxide/FOTS SAM layers. The duration of heat treatment in hours is shownon axis 1132, while the DI water contact angle for the SAM surface afterthe heat treatment is shown on axis 1134.

When the FOTS SAM layer was applied directly over the substrate, thetemperature stability of the organic-based SAM layer resulted in adecrease from an initial contact angle of about 111° to a contact angleof about 47° after a 24 hour exposure to a temperature of 250° C., asillustrated by Curve 1136. This compares with a constant contact angleat about 111° after the same 24 hour exposure to a temperature of 250°C., when the structure is a series of five pairs of silicon oxide/FOTSSAM layers, as illustrated by curve 1138.

The above described exemplary embodiments are not intended to limit thescope of the present invention, as one skilled in the art can, in viewof the present disclosure expand such embodiments to correspond with thesubject matter of the invention claimed below.

1. A method of depositing multilayered coatings on a substrate, whichcoatings are tailored to provide a particular characteristic behavior,wherein all layers of said multilayered coating are deposited from avapor phase, and wherein said multilayered coatings include a at leastone oxide-based layer and at least one organic-based layer.
 2. A methodin accordance with claim 1, wherein a plurality of oxide based layersare deposited.
 3. A method in accordance with claim 1, wherein saidvapor phase deposition employs a stagnant source of reactive moitiesduring the formation of each layer of the coating, which source ofreactive moities is depleted as the layer deposition continues.
 4. Amethod in accordance with claim 1 or claim 3, wherein said method iscarried out using a stepped addition of reactive moities to be consumedduring deposition of a coating layer.
 5. A method in accordance withclaim 4, wherein said coating layer is deposited using a series ofstepped addition and mixing steps during deposition.
 6. A method inaccordance with claim 1 or claim 3, wherein a plasma treatment iscarried out after the deposition of each organic-based layer which isnot the final surface layer of the coating.
 7. A method in accordancewith claim 1 or claim 3, wherein said plurality of oxide-based layersand organic-based layers are deposited so that an oxide-based layeralternates with an organic-based layer.
 8. A method in accordance withclaim 1 or claim 3, wherein prior to deposition of a first organic-basedlayer on a substrate, an oxide-based layer is applied over saidsubstrate.
 9. A method in accordance with claim 8, wherein an exposedsurface of said oxide-based layer contains —OH moieties.
 10. A method inaccordance with claim 8, wherein an exposed surface of said oxide-basedlayer contains halogen moieties.
 11. A method in accordance with claim10, wherein said halogen moieties comprise chlorine.
 12. A method inaccordance with claim 8, wherein prior to deposition of said oxide-basedlayer, said substrate is treated using an oxygen-based plasma.
 13. Amethod in accordance with claim 8, wherein said oxide-based layer isdeposited in the presence of an oxygen-containing plasma.
 14. A methodin accordance with claim 1 or claim 3, where more than 50% of thethickness contribution to the multilayered coating is provided by saidplurality of oxide-based layers.
 15. A method in accordance with claim8, wherein said oxide-based layer is formed by a reaction between achlorosilane vapor and water vapor.
 16. A method in accordance withclaim 15, wherein said chlorosilane vapor and said water vapor reactessentially on said substrate surface.
 17. A method in accordance withclaim 15, wherein a combination of a partial pressure of a chlorosilanevaporous precursor and a partial pressure of a water vapor precursor areused to control said reaction between said chlorosilane precursor andsaid water precursor.
 18. A method in accordance with claim 17, whereinsaid chlorosilane is selected from the group consisting oftetrachlorosilane, hexachlorosilane, hexachlorosiloxane and combinationsthereof.
 19. A method in accordance with claim 17, wherein a totalpressure in said process chamber ranges from about 0.5 Torr to about 30Torr, and a partial pressure of said chlorosilane vaporous precursorranges from about 0.5 Torr to about 15 Torr.
 20. A method in accordancewith claim 19 wherein a substrate temperature during deposition of saidoxide ranges from about 15° C. and about 80° C.
 21. A method inaccordance with claim 20, wherein a temperature of a major processingsurface inside said processing chamber ranges from about 20° C. to about100° C.
 22. A method in accordance with claim 17, wherein a partialpressure of said water vapor precursor ranges from about 0.5 Torr toabout 20 Torr.
 23. A method in accordance with claim 17, wherein,subsequent to the deposition of said oxide and the creation of hydroxylgroups on said oxide surface, a vaporous organo-chlorosilane whichincludes a specific functional group is reacted with said hydroxylgroups to impart specific functional characteristics to said coating.24. A method in accordance with claim 23, wherein a partial pressure ofsaid organo-chlorosilane vaporous precursor is used to control saidreaction between said organo-chlorosilane precursor and said hydroxylgroups so that said reaction occurs substantially on said substratesurface.
 25. A method in accordance with claim 24, wherein said reactionoccurs essentially on said substrate surface.
 26. A method in accordancewith claim 23 wherein said organo-silane vaporous precursor includes afunctional moiety selected from the group consisting of an alkyl group,an alkoxyl group, an alkyl substituted group containing fluorine, analkoxyl substituted group containing fluorine, a vinyl group, an ethynylgroup, an epoxy group, a glycoxy group, an acrylo group, a glycolsubstituted group containing a silicon atom or an oxygen atom, andcombinations thereof.
 27. A method in accordance with claim 26, whereina total pressure in said process chamber ranges from about 0.5 Torr toabout 30 Torr, and a partial pressure of said organo-chlorosilanevaporous precursor ranges from about 0.1 Torr to about 10 Torr.
 28. Amethod in accordance with claim 27, wherein a substrate temperatureduring deposition of said organo-chlorosilane vaporous precursor rangesfrom about 15° C. and about 80° C.
 29. A method in accordance with claim28, wherein said temperature of said major process surface ranges fromabout 20° C. to about 100° C.
 30. A method of depositing a multilayeredcoating on a substrate from a vapor phase, wherein each layer depositionrate is controlled by controlling a total pressure in a processingchamber in which said coating is deposited, a partial pressure of atleast one coating precursor, a temperature of a substrate on which saidcoating is deposited, and at least one temperature of a major processingsurface inside said processing chamber.
 31. A method of depositing amultilayered coating on a substrate from a vapor phase, wherein eachlayer deposition rate and a surface roughness of said multilayeredcoating are simultaneously controlled by controlling a total pressure ina processing chamber in which said coating is deposited, a partialpressure of at least one coating precursor, a temperature of a substrateon which said coating is deposited, and at least one temperature of amajor processing surface inside said processing chamber.
 32. A method ofcontrolling the surface roughness of a multilayeredorgano-silicon-containing coating on a substrate, wherein saidmultilayered coating is deposited from a vapor phase, wherein at leastone layer is formed using an organosilane precursor which is introducedinto a coating deposition chamber in which said multilayered coating isdeposited, followed by the introduction of water vapor, and wherein saidsurface roughness of said at least one layer is further controlled bycontrolling a total pressure in said deposition chamber, a partialpressure of at least one precursor, and a temperature of a substrate onwhich said coating is deposited.
 33. A method in accordance with claim32, wherein at least two organosilane precursors are introduced intosaid coating deposition chamber, followed by the introduction of water,whereby controllable co-deposition of said organosilane precursors isobtained.
 34. A method in accordance with claim 32, where a partialpressure of each precursor is controlled to adjust said surfaceroughness of said organo-silicon-containing coating.
 35. A method inaccordance with claim 32, wherein a partial pressure of said water vaporprecursor is controlled to adjust said surface roughness of saidorgano-silicon-containing coating.
 36. A method of depositing amultilayered coating wherein an oxide-based layer thickness in directcontact with a substrate is controlled as a function of the chemicalcomposition of said substrate, and wherein a SAM organic-based layer isdeposited directly over said oxide-based layer, whereby an ability ofsaid SAM organic-based layer to bond to said oxide-based layer isimproved due to control of said oxide-based layer thickness.
 37. Amethod of depositing a multilayered coating over a substrate, comprisingdeposition of at least two oxide-based layers and at least oneorganic-based layer, where each layer is deposited from a vapor phase,wherein said oxide based layer and said organic-based layer arealternated, and wherein an oxide-based layer is deposited directly overa surface of said substrate.
 38. A method in accordance with claim 37,wherein said multilayered coating includes at least two oxide-basedlayers and at least two organic-based layers.
 39. A method in accordancewith claim 38, wherein said multilayered coating includes at least fiveoxide-based layers and at least five organic-based layers.
 40. Astructure comprising a substrate with a multilayered coating depositedover a surface of said substrate, wherein said multilayered coatingcomprises a SAM organic-based layer deposited directly over anoxide-based layer which is deposited directly over said substrate, andwherein a thickness of said oxide-based layer which is in direct contactwith said substrate is controlled as a function of the chemicalcomposition of said substrate, whereby an ability of said SAMorganic-based layer to bond to said oxide-based layer is improved.
 41. Astructure in accordance with claim 40, wherein said multilayered coatingcomprises at least two oxide-based layers and at least one organic-basedlayer, wherein an oxide-based layer and an organic-based layer arealternated.
 42. A structure in accordance with claim 41, wherein saidmultilayered coating comprises at least two oxide-based layers and atleast two organic-based layers, wherein an organic-based layer forms thesurface of said multilayered coating.
 43. A structure comprising asubstrate with a multilayered coating applied over a surface of saidsubstrate, wherein said multilayered coating comprises a SAMorganic-based layer deposited directly over an oxide-based layer whichis deposited directly over said substrate, wherein said multilayeredcoating includes alternating layers of oxide-based material and SAMorganic-based material.
 44. A structure in accordance with claim 43,wherein said multilayered coating includes at least two oxide-basedlayers and at least one SAM organic-based layer.
 45. A structure inaccordance with claim 44, wherein said multilayered coating includes atleast two oxide-based layers and at least two SAM organic based layers.